10K bulbs dangerous to life?
JohnT
kind of lighting system. Anyone heard of Formosa Deluxe (4x55)220Watt, 48
inch by JBJ? Any comments?
The following is talking about 6500 being the natural intensity of Sun at
high noon. So is it healthier at 6500 than 10,000? Or do you think I can
save money by buying a smaller 10K?
http://www.angelfire.com/ca7/livestockusa/LIVEROCK.html
LIGHT
An important note ... remember the sun at
high noon on the equator is only 6500 Kelvin.
That means, less at other times of the day, or in
overcast, etc., etc. There is no 10,000 Kelvin
in the wild. There is no such animal.
It is often the overlighting of these new
super bulbs, which can kill corallines, and
corals. They ARE a marvel of technology,
but the product they put out is nothing any
animal in the sea is adapted to, or has ever seen.
I watched a large wholesaler in L.A. once
replace all his 10K's with 20K's when they came out,
and watched 500 beautiful purple and blue
acroporas turn brown in 2 days! So, let's be
careful with the light out there folks!
Jerry Baker
>
> I am planning to go reef instead of fish-only so I'm looking at different
> kind of lighting system. Anyone heard of Formosa Deluxe (4x55)220Watt, 48
> inch by JBJ? Any comments?
>
> The following is talking about 6500 being the natural intensity of Sun at
> high noon. So is it healthier at 6500 than 10,000? Or do you think I can
> save money by buying a smaller 10K?
The thing is that ocean water absorbs the red part of the spectrum
rather quickly. Even at relatively shallow depths the sunlight is nearly
pure blue. This is the situation that higher color temp bulbs are trying
to simulate.
--
Jerry Baker
Remove "fishies" to reply
EVER HEARD OF A BUSINESS SUING ITS CUSTOMERS?
www.petSwarehouse.com does.
Miles
actinic. It's worked fine for me. I bought mine from 6th Avenue Aquarium in
San Francisco. Much cheaper than the stores here in Phoenix. The light has
been fine but I think the newer ones are better. Mine does not have seperate
power cords for the two types of lights. The newer ones I believe do. The
fans wore out after only two months and I had to replace them but was no
big deal. Otherwise the light is well made. I bought the JBJ stands to lift
it up
about 3" as it helps with the heat.
Jimmy Chen
> high noon. So is it healthier at 6500 than 10,000? Or do you think I can
> save money by buying a smaller 10K?
We keep our corals in the water, not above the water surface ... Sun's
intensity and K above the surface is meaningless for us.
--
jc
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Chief Ephor
I am not a big fan of JBJ, and I personally would rather go with 2X96W
instead of 4X55W. Save you money in the long run. I am sure JBJ will come
out with 10X27W, and people will buy them.
Anyway, let me comment on the quote. The author does not sound like he/she
know what is being said. Indirect sunlight (reflection from the sky) has a
much higher Kelvin than 6500K. I work in a tall building, and the light
from the window is about 10,000 to 20,000 Kelvin. During overcast, the
Kelvin rating also can go up because the indirect blue light from the sky.
Physicists made calculations and measurements, and anyone who do a search on
the web or a library should be able to verify the above facts.
For the below water scenerio, I am not going to say anything. But notice
that the quote's author say that "There is no 10,000 Kelvin in the wild,"
and went on to say that "nothing any animal in the sea is adapted to." But
in the second paragraph, the author mentioned that an LA wholesaler has 500
beautiful purple and blue acroporas under the 10,000 Kelvin bulb.
Anybody can put up a web page nowadays. Anyone can reply to a USENET post.
bye -ck-
Ed Hughes
For our purposes it's an aesthetic issue. People have grown corals
successfully with 5.5KK, 6.5KK, 10KK, 12KK, 14KK, and 20KK bulbs. Most
people like the look of the 10's better than the 5.5's, while other people
like that the 6.5 makes more PAR at the same wattage than the 12 (MH bulbs,
I don't know if this applies to PC or not.) At any rate, neither choice is
intrinsically wrong.
Lighting is probably the single most confusing topic there is, and if you
search this group in Google you find literally thousands of posts on it.
Good luck,
Ed
"JohnT" <whosj...@gus.net> wrote in message
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JohnT
"Chief Ephor" <seven_...@hotmail.com> wrote in message
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> hi.
> I am not a big fan of JBJ, and I personally would rather go with 2X96W
> instead of 4X55W. Save you money in the long run. I am sure JBJ will
come
> out with 10X27W, and people will buy them.
Thanks for the input. I know JBJ isn't probably the best out there but from
the store that I visited, they seem to take care of the reef just fine and
it is aethetically not too bad looking. Also, I want a compact one over MH,
mine is only 60 gallon @ 48in. What would you recommend then for my tank?
Chief Ephor
> mine is only 60 gallon @ 48in. What would you recommend then for my tank?
hi.
As I mention in the previous post, use the 96Watters. For 60 gal, depends
on what you want to keep, two or three 96 watters should be fine. Does JBJ
have 2X96 PC setup?
bye -ck-
Jimmy Chen
> people like the look of the 10's better than the 5.5's
While the corals will grow, most corals also tends to be a lot more brown
with 5.5K bulbs, according to Dana Riddle.
, while other people
> like that the 6.5 makes more PAR at the same wattage than the 12 (MH
bulbs,
> I don't know if this applies to PC or not.)
What is funny is people try to save money on the MH by going 6.5K, but they
turn aroun and have to supplement the green/yellow color with an additional
VHO/PC setup which is just as expensive. Their whole setup is now even more
expensive and then they complain how come MH setup is so expensive ... All
of this could have been very easy dealt with by going with 10KK bulbs to
begain with, and if the PAR isnt strong enough, get the next more intensive
wattage.
--
jc
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At any rate, neither choice is
Ed Hughes
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:kyIs8.110965$in3.30...@typhoon.nyc.rr.com...
> > Most
> > people like the look of the 10's better than the 5.5's
>
> While the corals will grow, most corals also tends to be a lot more brown
> with 5.5K bulbs, according to Dana Riddle.
>
I don't doubt that, and I sure don't like the look of 5.5's myself. Do you
know if the color difference is actual or perceived?
> , while other people
> > like that the 6.5 makes more PAR at the same wattage than the 12 (MH
> bulbs,
> > I don't know if this applies to PC or not.)
>
> What is funny is people try to save money on the MH by going 6.5K, but
they
> turn aroun and have to supplement the green/yellow color with an
additional
> VHO/PC setup which is just as expensive. Their whole setup is now even
more
> expensive and then they complain how come MH setup is so expensive ... All
> of this could have been very easy dealt with by going with 10KK bulbs to
> begain with, and if the PAR isnt strong enough, get the next more
intensive
> wattage.
No argument there. I already had VHO before I got MH, and I like the look
that the VHO actinics give, so for me it was a natural to take the higher
PAR and longer life of the Iwasaki light. Maybe the cost still comes out
higher, but that is ok -- it's my tank and it's what I like.
Do you really think the "MH is too expensive" argument is valid anyway? I
mean, they are all expensive, and especially if you are handy and can handle
a little DIY, MH is no more expensive than any other. Then factor in
frequency of bulb replacement, how much easier it is to cool an MH light
than the others, and MH efficiency, and MH starts to look comparitively
cheap.
Best regards,
Ed
Joe Graeber
:)
In any case, who/what is JBJ ?
Joe
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:zsCs8.110675$in3.30...@typhoon.nyc.rr.com...
Captain Michael Huett
This is a color temperature not a heat or intensity rating. 10,000 degrees
is simulating more blue light recieved at depth.
.
"JohnT" <whosj...@gus.net> wrote in message
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Joe Graeber
or VHO setup for actinics in addition to the 10k MH either way though.
Dunno, I hate talking about lighting ... it's too 'personal', like claiming
Speaker A sounds better than Speaker B.
Bottom line based on what I've ready: 10k bulbs aren't dangerous to life.
:)
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:kyIs8.110965$in3.30...@typhoon.nyc.rr.com...
Jimmy Chen
A PC light fixture brand ...
jc
Jimmy Chen
> know if the color difference is actual or perceived?
Actual ...
http://www.masla.com/reef/lightingbasics.html
"Coral Farming
Coral farming presents some special considerations. The goal is usually to
produce salable colonies in the quickest manner possible, while keeping
costs under control. The key to sales is usually dependent on the color of
the coral (especially SPS colonies). Based on years of experience, I'll
make two specific recommendations. We've used 175 watt Feit and Philips
low Kelvin metal halide lamps (around 3,500 - 4,000 K) with excellent
results in standard Coralife fixtures (technically called luminaires).
These are particularly effective over aquaria with depths not exceeding 12
inches (we used eggcrate supported by PVC pipe to "elevate" the corals
closer to the light ). These lamps are inexpensive - usually less than $20
each at Home Depot. Colors of SPS corals are usually apparent under these
lamps but some of the green soft corals (such as Sinularia) appear washed
out under these lights. As a footnote, we were disappointed by the
apparent color of some soft corals under these lamps - and so were our
customers, we couldn't give these corals away! Only when we displayed
these under daylight/actinic combinations or some of the 10,000 - 20,000 K
lamps did the startling green coloration become apparent. The problem was
then growing enough of these!"
> Do you really think the "MH is too expensive" argument is valid anyway? I
> mean, they are all expensive
Not really. A while back I compared 2x4x96w PC vs 2x250w/400w 10KK MH for
someone, they went with 250w MH ... The total difference in price was less
then 50 dollars.
> Then factor in
> frequency of bulb replacement, how much easier it is to cool an MH light
> than the others, and MH efficiency, and MH starts to look comparitively
> cheap.
Well, 10KK MH = $100 blub avg, x 2 ... replace one per year ... so $200
PC = ~40 each, replace every 6~8 mo ... so 4x avg = $240/yr if we go by 8 mo
s
VHO = $~30, replace every 6 mos ... 4x avg = $240
Price wise PC, VHO, MH is pretty much the same. If we were talking about
5-10 years ago when 10KK, 12KK or 20KK MH bulbs were new, then I understand
the MH being more expensive argument. However, nowadays they are cheap so
its time to drop that argument and make it a non-issue.
jc
Gary Taylor
VHO actinics allow you to more closely simulate sunrise/sunset than just
having the MH? This was my thinking when I purchased my VHO (actinic/6500K)
setup, with the intent of upgrading later by adding 6500K MH (and using 2
actinic VHO bulbs) when I got comfortable with FOWLR and wanted to upgrade
to full blown reef.
Or were you just commenting on the total $$ involved for using MH
supplemented with VHO?
--
Gary Taylor
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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Jimmy Chen
with
> VHO actinics allow you to more closely simulate sunrise/sunset than just
> having the MH?
This is one argument for such a setup ... But Richard Harker have in his
article that at 8:30am, the sun is already pushing as much intensity as a
400w MH bulb couple of inches away. So in our case, even with 400w bulb, we
arent pushing the kind of intensity normal sun light is producing during the
day.
The other side of that is, VHO creates the dawn/dust period ... In the
morning I know by the time my 2x150w turns on around 10-ish AM, the corals
and fish are as active as normal day time. As for at night ... As soon as
the lights turn off, they go into the sleep mode right away. So I dont see
any ill effect from not having dawn/dust cycles.
Besides, the other counter is MH doesnt just turn on like VHO or PC, so it
actually provides enough adjustment time for the corals and fish and is less
"shocking" then VHO or PC.
jc
JohnT
I don't think JBJ carry 2x96. Why is it so important? Power consumption?
I just bought 4x55 for $299 at a local store (not bad pricing). Remember
there are two kinds of 4x55 JBJs, make sure you get the Deluxe not the
Double. The cost is something like 25%-35% more. Deluxe MSRP is around
$400-$500. I'm sure this light will be more than sufficient for my 60
gallons. BTW, it's 10K white and blue, covering more spectrum. =) <smile>
One nice thing about these LBJ is that the hood has a +98% reflector.
"Chief Ephor" <seven_...@hotmail.com> wrote in message
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Captain Michael
rating, the bluer the light. Simulating the deeper water. SPS corals seem to
like light close to the surface. The browning effect refered to probably
occured because of not enough light rather than too much.
"JohnT" <whosj...@gus.net> wrote in message
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Boomer
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > I'm not expert, but wouldn't going with 6500K MH, and supplementing
:
:
Jimmy Chen
really looked at this
What do you mean by K change? Changes from dawn to dust? I havent seen any
article on this subject ...
jc
Jimmy Chen
> like light close to the surface. The browning effect refered to probably
> occured because of not enough light rather than too much.
So logically speaking, by being limited to keeping the SPS to the surface,
switching to a more intensive light also means you can now place the same
corals lower in your tank and they can still ve receive the same amount of
light as they were under the less powerful light at a higher placement.
So we have ...
Weak light = higher placement, less color
Strong light = lower placement, more color
jc
Chief Ephor
hi.
Well, if you read my first post on this thread, you will see that I said "I
am sure JBJ will come out with 10X27W, and people will buy them." My point
is that the replacement cost of the bulbs make 2X96W a better choice
economically. There is very little price difference between 96W and 55W.
Same argument applies to 3X175W MH , 2X250W or 1X400W. The bulb in MH will
last longer than PC, but the cost of ballast is something that we to take
into account. Of course we also need to consider the length of the tank.
If the tank is shallow 8 feet with only mushrooms, then 3X175 will give a
more uniform illumination. Etc..
But it seem to me that many people quit the hobby withing one or two years,
so replacement cost may not be that big of a deal.
bye -ck-
Boomer
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > All true, but what about that K change ? I'm wondering if anyone has
:
:
Jimmy Chen
LOL, I know THAT, dude ... What I dont know is what you meant by K change
... Change in respect to what?
jc
Boomer
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > All true, but what about that K change ? I'm wondering if anyone has
:
:
Boomer
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > SPS corals seem to
:
:
Boomer
have in respect to coral growth and color, be in on a reef or tank. I don't recall any
studies. How would/could corals benefit, if there is a benefit or would they show it is
meaningless. Cyclic K must have some bearing on corals to some degree.
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > K=Kelvin
:
:
Jimmy Chen
it have/might
> have in respect to coral growth and color, be in on a reef or tank.
This was what I assumed you meant the first time ...
I don't recall any
> studies. How would/could corals benefit, if there is a benefit or would
they show it is
> meaningless. Cyclic K must have some bearing on corals to some degree.
Me neither, so it is a question that we currently dont have a answer for ...
It may be an interesting subject for a researcher to do some study on ...
However, I dont know if daily K cycles would have as much effect on
coloration as seasonal K cycles ... But one question in respect to this tho
... Since ocean water filters out whatever wavelength it does, does it
matter what angle the sun is at? I would think not because it will still be
the same kind of wavelength filtering happening ...
jc
Boomer
matter what angle the sun is at? "
Yes, it does make a different what angle it is, as the light is refracted different at
other angles as it parts the water. Angle alone can change K values
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
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: > K changes from dusk to dawn with natural sunlight, thus what bearing would
:
:
John&Jana
matter what angle the sun is at? I would think not because it will still be
the same kind of wavelength filtering happening ...
I would disagree. The angle of the sun is what causes change in intensity. It's
the same as why it's hotter in the summer-the sun is hitting us at a more direct
angle as the earth changes it's axis of rotation. When it hits on an angle,
there is less absorption as much of it it deflected, and therefore less
intensity. Am I making any sense here?
John
http://www.freewebz.com/jjdhome/Index.htm
Jimmy Chen
Agreed. I am not questioning this part of the equation. What I am
questioning is the K value. Boomer seems to think the angle of the sun will
cause a change in K valve. I dont believe it will.
My logic for thinking it wont is because ocean water will filter out the
same wavelength at the same depth no matter what the intensity is. So at a
given depth, if all that is detected is the 400~550nm range, we will have
only have the 400~550nm range, no matter if it is sunny or cloudy day,
summer or winter. In this case how many "watts" will change, but the K valve
wont.
jc
Jimmy Chen
different at
> other angles as it parts the water. Angle alone can change K values
Then shouldnt the ocean be different colors during different seasons?
jc
John&Jana
same wavelength at the same depth no matter what the intensity is. So at a
given depth, if all that is detected is the 400~550nm range, we will have
only have the 400~550nm range, no matter if it is sunny or cloudy day,
summer or winter. In this case how many "watts" will change, but the K valve
wont.
Ok. But isn't penetration of water depth is directly related to intensity?.
Therefore, wouldn't you have higher spectrum peaks at lower levels as the
intensity was increased?
John
Jimmy Chen
intensity?.
> Therefore, wouldn't you have higher spectrum peaks at lower levels as the
> intensity was increased?
I could be wrong, but I dont believe it makes much of a difference ... If
you look at the chart from MCRA vol 1 pg 198, most of the light above 600nm
are filtered out by the first 20~40m, whereas under 600nm can reach as deep
as 100m ... So weither it is full sunny day or not, you still arent going to
see anything above the 600nm at 40m depth, whereas you will see plenty of
blue/green.
Then there is the chart on the next page 199, showing at 20m depth the
mix-max lux differs only by 4000 lux and at 100m by only 20 lux.
jc
Boomer
If you measured the K values a different seasons/time of day there is a variation in K.
Check any source on light physics in water and the angle light imparts on it (Incident
Angle). If light hits a refracting/reflecting media at 90 degrees (vertical) vs 30 degrees
it is not the same, how can it be ? And reflection plays a bigger role than refraction.
Think of a lap-top pc and its LCD screen and how you have to move it around to get the
screen to look right. The only thing affecting it is the angle the light hits it and if it
had no effect you wouldn't be moving it around.
You know the K value changes from dawn to dusk, be it water or air. The K at noon is not
the same as 2:00 PM. So question, what is causing the K change ? It is not intensity, you
can have 1 W@ 6500 K or 500 W @ 6500 K. Intensity does not change color. The sun is
burning the same at noon as it is at 2:00 PM, so it is not the sun changing. Yup, it is
higher and more intense @ noon but what is changing its K ? The only thing left is the
incident angle of the sun to the atmosphere, a refracting, reflecting media and water is
also a refracting, reflecting media. Or do I have it all wrong ?
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:r76t8.114265$in3.31...@typhoon.nyc.rr.com...
: > Yes, it does make a different what angle it is, as the light is refracted
:
:
Jimmy Chen
> The only thing left is the
> incident angle of the sun to the atmosphere, a refracting, reflecting
media and water is
> also a refracting, reflecting media.
Right, I agree with all this ... What I am questioning is by the time any
light of any K value hits the water, most of the upper nm wavelength is all
filtered out by the ocean within meters so by this nature in itself
indicates only certain K rating can reach the depths, no matter what K hits
the surface initially. It is like you can hit a blue filter with red, white,
green, yellow, blue. But if only blue can pass thru, it doesnt matter what
other colors are, they just wont get thru. That is why I dont see changes in
K value matters.
jc
Ross Bagley
Jimmy Chen <ji...@reefkeepers.DOTorg> wrote:
>> You know the K value changes from dawn to dusk, be it water or air.
>
>> The only thing left is the
>> incident angle of the sun to the atmosphere, a refracting, reflecting
>media and water is
>> also a refracting, reflecting media.
>
>Right, I agree with all this ... What I am questioning is by the time any
>light of any K value hits the water, most of the upper nm wavelength is all
>filtered out by the ocean within meters
If you shine a really bright monochromatic red light into the ocean on
a moonless night, what will you see at various depths? Turns out
you'll see a dimmer and dimmer red light until you can't make it out
any more. Same thing with a monochromatic blue light, but you'll see
the blue light clearly much deeper.
A redder source (lower color temperature, measured in K) will be
redder in the ocean. As you go deeper, however, the color temperature
of all broad spectrum sources increases as the colors outside of the
bluish transmission spectrum are gradually suppressed.
>so by this nature in itself indicates only certain K rating can reach
>the depths, no matter what K hits the surface initially.
The color temperature in the depths will always be hotter (higher K)
than at the surface or shallow, but a redder light source (like the
sun at sunset) will generate cooler (lower K) color temperatures than
a bluer light source (like the sun at noon), even in the depths.
Go scuba diving in the twilight on a shallow reef to see what I mean.
The reds and oranges really come alive for those few minutes.
Regards,
Ross
-- Ross Bagley http://rossbagley.com/rba
"Security is mostly a superstition. It does not exist in nature...
Life is either a daring adventure or nothing." -- Helen Keller
Jimmy Chen
> a moonless night, what will you see at various depths? Turns out
> you'll see a dimmer and dimmer red light until you can't make it out
> any more. Same thing with a monochromatic blue light, but you'll see
> the blue light clearly much deeper.
Right, and this is what I am saying; that no matter how the K valve changes
due to sun angle in different seasons, the water will still filter the
higher nm ranges out first as you go deeper ... So having more red in the
morning compared to less red at noon really doesnt matter when you are 20m
deep.
jc
Ross Bagley
True. But is everyone trying to model a reef at 20m? There is a
lot of interest in corals and plants that are adapted to the surf
and surge of the near surface region.
Who knows the effect of more closely modeling sunrise and sunset
for these beasties?
Boomer
depth.Where did that come from ? I'm quite familiar with light extinction in water.
:"Since ocean water filters out whatever wavelength it does, does it
:matter what angle the sun is at? "
:Yes, it does make a different what angle it is, as the light is refracted different at
:other angles as it parts the water. Angle alone can change K value"
When light hits a refracting/reflecting media, such as water, the angle that light hits
that media gives a different color band.
If we aim a beam of light at a drop of water that imparts an angle of 40-42 degrees the
color band produced goes from violet to red, if we now change it to 50-54 degrees the
color band changes from red to violet. One of the single most important things in light is
its incident angle, which is the angle it hits something
Maybe you missed it. If it is high noon and light hits the water, vs. 2:00 PM , you do not
have the same K value, because the light is at a different angle to the water.
You haven't answered any of my imposed questions. What then changes the K value of light
between noon and 2:00 PM. Only the incident angle it meets with the atmosphere, a
refracting/reflecting/absorbing body.......as is water. So why would the atmosphere change
the K value and not water, if the incident angle is different ? Are you say only
absorption/extinction rules and we just throw out refraction and reflection ?
Boomer
WCWing@Chartermi..net
If You See Me Running You Better Catch-Up
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:OPmt8.88757$9N1.8...@typhoon.nyc.rr.com...
: > If you shine a really bright monochromatic red light into the ocean on
:
:
Jimmy Chen
absorption with
> depth.Where did that come from ? I'm quite familiar with light extinction
in water.
Hmm, we are talking about light in the water, and not light in the air,
right?
> :Yes, it does make a different what angle it is, as the light is refracted
different at
> :other angles as it parts the water. Angle alone can change K value"
I already said I agreed with you on that ... Different angles changes the K
value hitting the water isnt what I am questioning ...
> When light hits a refracting/reflecting media, such as water, the angle
that light hits
> that media gives a different color band.
In AIR ...
> If we aim a beam of light at a drop of water that imparts an angle of
40-42 degrees the
> color band produced goes from violet to red, if we now change it to 50-54
degrees the
> color band changes from red to violet. One of the single most important
things in light is
> its incident angle, which is the angle it hits something
Again, in AIR ...
> Maybe you missed it. If it is high noon and light hits the water, vs. 2:00
PM , you do not
> have the same K value, because the light is at a different angle to the
water.
Correct, and I agree with what you said here ...
> Are you say only
> absorption/extinction rules and we just throw out refraction and
reflection ?
What I am questioning is ... Lets assume the first 5m of water filters lets
say 50% of the red, and 20m will filters out 80%, who cares what angle the
red hits the water at? Fact of the matter is, 50% will get filtered out by
the first 5m and 80% at 15m.
So why would it matter if you hit the water with 50 megawatts of red at 8am,
and only 10 megawatt at 12 noon? Either way, by the time you reach 15m, only
20% of the total spectrum is red that depth is red.
jc
Jerry Baker
>
> > Stop trying to confuse and change the issue. This is the issue and not
> absorption with
> > depth.Where did that come from ? I'm quite familiar with light extinction
> in water.
>
> Hmm, we are talking about light in the water, and not light in the air,
> right?
Last I was outside I noticed that the sunlight had to pass through a
considerable amount of air before even making contact with the water ;-)
--
Jerry Baker
Remove "fishies" to reply
EVER HEARD OF A BUSINESS SUING ITS CUSTOMERS?
www.petSwarehouse.com does.
JohnT
bargain $299 for 4x65Watters. I am quiet satisfy as I check the pricing on
this JBJ retail at $520 and I really like the look of the lights on my Tonga
rocks and live sand with both independent switches for blue(7.1K) and
daylight (10K).
While MH may be the best for larger tank but wouldn't you think MH would be
an overkill for my 48"x18"x18" 60 gallon tank? Oh, by the way, JBJ does
make doubles at 2x96Watts. See here
http://www.jbjlighting.com/sys_formosa_dx.html . Anyways, I think Formosa
is a nice Power Compacts. I like the heat dissapation hood material; well
built. Of course it comes with dual fans, on when the 10K lights are on
(but overridable with a switch to turn them off, I see no point in doing
that unless it's winter and you live in an extremely cold area where you
need heaters; but again, the fan on would act as a mini heater, lol). What
I do is longer blue lights of 9-10 hours with no fan while the 10K white on
for 8 hours; during the time when only the blue is on, the fans are off;
when whites are on, dual fans kicks in. During the last hour at night, only
the blue is on, fan off. Night time, it's cooler anyways; not a problem.
-JohnT
"Chief Ephor" <seven_...@hotmail.com> wrote in message
news:a91kdn$4gf$1...@news.service.uci.edu...
Jimmy Chen
> considerable amount of air before even making contact with the water ;-)
Correct, this is why I agree with all the K value changes in the air ... But
the issue I am still questioning is if water filters out all of the upper nm
wavelengths, does it really matter what the intensity is for a given K value
when it hit the water?
Lets assume all the red is filtered out by the first 15m, it is all filtered
out, period. It doesnt matter if you are hitting the surface with 5
megawatts or 5,000 megawatts of red. At 15m, you will have zero watt. This
is no different then the color filter for light. If a blue filter only
allows blue light to pass, it doesnt matter what bulb you use behind the
filter to power it. You are only going to see blue. Is this all a moot issue
because the K value can change in the air?
jc
Boomer
confused
"So why would it matter if you hit the water with 50 megawatts of red at 8am,
and only 10 megawatt at 12 noon?"
When the light hits the water at angle it changes its K in the first few inches as
opposed to changing its K when it hits at the vertical. We are not talking about light
absorption. but refraction and reflection. Lets change your values so it is clear. 25 megs
of red at 8 am and 25 megs at noon and now we measure the K value immediately at the
surface and immediately under the water at both points/angles. The amount of red light
hitting just above the surface is the same at both angles, as nothing is interfering with
it, but right at the surface and just under the water it has changed, do to reflection and
refraction, because the way light is scattered/reflected at different angles, so we now
have _LESS_red light in the water column traveling to any depth. So if we are after red
light at some depth, now there would be less red light at that depth wouldn't there. 50
megs of red light travels father thought the water column than 10 megs and you are making
sound like it make no difference
"Either way, by the time you reach 15m, only
20% of the total spectrum is red that depth is red.
and what is 20 % of 50 =10 megs and 20 % of 10 = 2 megs
"who cares what angle the
red hits the water at? Fact of the matter is, 50% will get filtered out by
the first 5m and 80% at 15m."
and what is 50% of 25 meg at 5m or 80 % of 25 megs at 15 m and if we lost 5 megs when it
hit the water then it is 50 % of 20 megs and 80 % of 20 megs and at some depth there will
still be light from the 25 megs and no light from the 20 megs
You are still confused, because there is LESS light to filter out from the start,
therefore less light going to any depth
Lets explain this nonsense statement " who cares at what angle" in kindergarten terms.
Take a flashlight and aim it straight down in your tank, notice how the corals and bottom
are lit up, measure its intensity and K at the bottom, now take the flashlight and hold it
parallel to the water and notice how nothing is lit up, but you say angle makes no dif.
Now hold the light at a 45 degree angle to the water and notice the results are in between
the two. If you measure the K above the water at vertical and measure the K just below the
water they are not the same and if you now impose an angle to it, the K value at the
surface is still the same, but is even more different than the K you got a vertical just
under the water when you impose an angle and measure it under the surface. If for example
it was 6500 K at the surface at vertical and say 6400 K just under the water at vertical
and we now imposed an angle to it would till be 6500K at the surface but would now be say
6300 K just under the surface, so we now have less blue light for our corals. At vertical
we had more blue light reaching the corals and at some imposed angle we now have less blue
light reaching the corals. I can't be anymore clear. Incident angle in water or air
changes things.......period
Please Join Our Growing Membership
www.coralrealm.com
Boomer
WCWing@Chartermi..net
If You See Me Running You Better Catch-Up
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:Vnrt8.88812$9N1.8...@typhoon.nyc.rr.com...
: > Stop trying to confuse and change the issue. This is the issue and not
:
:
Boomer
". It doesnt matter if you are hitting the surface with 5
megawatts or 5,000 megawatts of red. At 15m, you will have zero watt. "
Forget 15 m and 0, lets go with 5 m or 10 m
Yes or No
Is there more red light at 5 m or 10 m from the original 5,000 megs than the original 5
megs
"Is this all a moot issue
because the K value can change in the air?"
Please explain in detail why K can change in air and not in water. If you measure the K
value at 5 m it is not the same as at 10 m...period
"does it really matter what the intensity is for a given K value
when it hit the water?
I don't believe you just made such a nonsense statement, it is almost funny
Ok, please explain why we just can't use florescent lamps rather than MH if the intensity
of K makes no difference ?
The intensity of the light values for fluorescent lamps in its SED curves is 0-2 watts /
10 nm band width and in MH it is 0-10 watts / 10 nm band width
When you look at one of those light spectrum graphs of a light bulb the vertical value is
its intensity and that intensity is in watts and if you combine all those watts and all
the colors you get a K value and a K value in watts. So your theory has it, that a
florescent light will penetrate water the same as a MH or if you want lets get down to two
bulbs that operate on a more similar bases such as MH and MV. So, if both bulbs produce
6500 K it should make no difference which one we use based on your theory, as the
intensity of the K value makes no difference when it hits the water. Please explain, in
detail, how a 400 watt MV which has a intensity of 0-10 watts and a 400 watt MH which has
a intensity of 0-20 watts, makes no difference as how much light is received at the
bottom in a 3 foot reef tank, because "does it really matter what the intensity is for a
given K value when it hit the water? " A 400 W MV will deminish in K and intensity with
depth more than a 400 W MH....period
--
Please Join Our Growing Membership
www.coralrealm.com
Boomer
WCWing@Chartermi..net
If You See Me Running You Better Catch-Up
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:VjDt8.88863$9N1.8...@typhoon.nyc.rr.com...
: > Last I was outside I noticed that the sunlight had to pass through a
:
:
Jimmy Chen
>
> Yes or No
Yes, we have different intensity of the given K at lesser depths ... But
here the intensity is what changed, not K valve, right?
> Please explain in detail why K can change in air and not in water. If you
measure the K
> value at 5 m it is not the same as at 10 m...period
You totally lost me here .. How can I explain something that I am trying to
understand? My understanding is that since light hit the ocean surface for
all pratical purposes it pretty much straight, we dont have conditions where
under the water light can projects any angle beams like we would see in the
air. If what you said is true with the K value changes due to light angles,
shouldnt we then also see the rainow effect under the water as well? But we
dont.
jc
Ross Bagley
Jimmy Chen <ji...@reefkeepers.DOTorg> wrote:
>> Forget 15 m and 0, lets go with 5 m or 10 m
>>
>> Yes or No
>
>Yes, we have different intensity of the given K at lesser depths ... But
>here the intensity is what changed, not K valve, right?
No, the color temperature continues to rise (higher K) the deeper you
go. All of the red light is not gone by 15m. A lot of it is gone,
but not all. All of the red light is not gone by 40m. Even more of
it is gone, but not all. As the average wavelength continues to
decrease, the color temperature does rise.
The deeper you go, the higher the color temperature. A 10,000K bulb
may be an accurate representation of noon sun at 20m. A 20,000K bulb
may be an accurate representation of noon sun at 30m.
Also, remember that these K values are *very* rough approximations of
an actual blackbody emission spectrum. The Iwasaki 50,000K bulb gets
that "color temperature" from a huge spike in the UVA band that knocks
the average way up (otherwise it looks like a weak 10,000K bulb), not
because it has a smooth emission curve similar to a 50,000K blackbody.
>> Please explain in detail why K can change in air and not in water. If you
>measure the K
>> value at 5 m it is not the same as at 10 m...period
>
>You totally lost me here .. How can I explain something that I am trying to
>understand? My understanding is that since light hit the ocean surface for
>all pratical purposes it pretty much straight, we dont have conditions where
>under the water light can projects any angle beams like we would see in the
>air.
Not quite any angle. You don't see sunlight beams at really shallow
angles, but you do see beams at different angles all the time. When
scuba diving, you'll use them for navigation (why check the compass
when the sunlight will tell you everything you need to know?). At
sunset, the changing color and angle is a big indicator to get back
to the boat while it's still easy to find...
>If what you said is true with the K value changes due to light
>angles, shouldnt we then also see the rainow effect under the water
>as well? But we dont.
Well, actually, you do see "rainbows" at every serious change in
refraction index (surface water to air, mask glass to air). It's
usually referred to as chromatic abberation when it impedes your
vision in your mask and it's a serious impediment to your peripheral
vision.
The "rainbows" from the surface interface can be difficult to make out
unless the surface conditions are ideal (small ripples on an otherwise
glass smooth surface) cause they get muddled together and turn into a
wash of light that just looks like a diffused version of the original
source.
Jimmy Chen
> go. All of the red light is not gone by 15m. A lot of it is gone,
> but not all. All of the red light is not gone by 40m. Even more of
> it is gone, but not all. As the average wavelength continues to
> decrease, the color temperature does rise.
>
> The deeper you go, the higher the color temperature. A 10,000K bulb
> may be an accurate representation of noon sun at 20m. A 20,000K bulb
> may be an accurate representation of noon sun at 30m.
Sorry Ross. I think you might have missed the beginning of this discussion.
The K valve change we are trying to figure out is not the change in respect
to depth, but in respect to sun rise / sun set and changes of seasons. So
basically we know sun intensity changes from morning to noon then to
evening. Question that Boomer asked was we know intensity has effects on
coral coloration. How about the K valve change in this same respect. ie: Sun
is at a different angle to the sun during Summer compared to Winter, morning
to afternoon, the morning may have more higher nm valves then noon, etc.
During this period, the K valve changes as well as intensity. Does the
change in K valve in this repsect has any effect on coral coloration.
My take on this is that the higher nm gets filtered out quickly, as you
indicated above as will, so it may not play a role, if any.
jc
Ross Bagley
Jimmy Chen <ji...@reefkeepers.DOTorg> wrote:
>> No, the color temperature continues to rise (higher K) the deeper you
>> go. All of the red light is not gone by 15m. A lot of it is gone,
>> but not all. All of the red light is not gone by 40m. Even more of
>> it is gone, but not all. As the average wavelength continues to
>> decrease, the color temperature does rise.
>>
>> The deeper you go, the higher the color temperature. A 10,000K bulb
>> may be an accurate representation of noon sun at 20m. A 20,000K bulb
>> may be an accurate representation of noon sun at 30m.
>Sorry Ross. I think you might have missed the beginning of this discussion.
I saw that, but it looked liek the confusion was due to a
misunderstanding of more fundamental issues. Based on the
specific questions raised in the post I replied to, it seemed
they were worth answering as asked, leaving out the issue of
the fact that sunlight gets a cooler color temperature (lower
K aka redder) in the morning and evening.
>The K valve change we are trying to figure out is not the change in
>respect to depth, but in respect to sun rise / sun set and changes of
>seasons.
But you can't separate one effect from the other. Deeper makes the
light higher K, morning or evening makes the sunlight (the source)
lower K. During sunset or sunrise a reef at 10m may see equivalent to
a 3000K spectrum with the srface spectrum being 2000K and the water
filtration making it a little hotter (bluer).
>So
>basically we know sun intensity changes from morning to noon then to
>evening. Question that Boomer asked was we know intensity has effects on
>coral coloration. How about the K valve change in this same respect. ie: Sun
>is at a different angle to the sun during Summer compared to Winter, morning
>to afternoon, the morning may have more higher nm valves then noon, etc.
>During this period, the K valve changes as well as intensity. Does the
>change in K valve in this repsect has any effect on coral coloration.
I'd hazard an informed guess that the effect would be subtle, but
real. ChlorophyllIIA and ChlorophyllIIB are red sensitive and would
be more strongly encourages relative to other photosynthetic chemicals
in a natural reef than one that receives steady 6500K light all day
long.
>My take on this is that the higher nm gets filtered out quickly, as you
>indicated above as will, so it may not play a role, if any.
Depends on how deep you want to model your reef. By 30m, few corals
are primarily relying on photosynthetic reactions and are doing other
things to gather energy. Shallower than that and the balance changes
dramatically.
Jimmy Chen
> misunderstanding of more fundamental issues. Based on the
> specific questions raised in the post I replied to, it seemed
> they were worth answering as asked, leaving out the issue of
> the fact that sunlight gets a cooler color temperature (lower
> K aka redder) in the morning and evening.
Correct. This is the part where I am pointing out the filtering out of the
higher nm ranges.
> But you can't separate one effect from the other. Deeper makes the
> light higher K, morning or evening makes the sunlight (the source)
> lower K. During sunset or sunrise a reef at 10m may see equivalent to
> a 3000K spectrum with the srface spectrum being 2000K and the water
> filtration making it a little hotter (bluer).
Agreed, and this why why I keep thinking it wont matter much because as we
go deeper, the lower K valves would have already been filtered.
> Depends on how deep you want to model your reef. By 30m, few corals
> are primarily relying on photosynthetic reactions and are doing other
> things to gather energy. Shallower than that and the balance changes
> dramatically.
I agree with this. Problem here is most of the systems are under-lited IMHO.
A lot of people still uses VHO/PC as their light, and those only produces
300~375 uMols/m2/sec at the surface using 4x110w or 4x96w. 400 uM is the
intensity measured at 63 ft ocean depth (Riddle). Even with 400w MH, it only
produces 2000 uM inches away from the bulb, which is what ocean surface
measures. In the ocean that intensity drops to 1000 uM at 20 ft. So at best
we are not doing any better then 20 ft in our tanks, and can be worst then
the intensity at 63 feet.
jc
Ed Hughes
"JohnT" <whosj...@gus.net> wrote in message
news:3cb678ed$1...@news.teranews.com...
<snip>
> While MH may be the best for larger tank but wouldn't you think MH would
be
> an overkill for my 48"x18"x18" 60 gallon tank? Oh, by the way, JBJ does
> make doubles at 2x96Watts.
Hi John,
I don't think it would be overkill at all. I'll tell you though, my LFS guy
looked at me like I was crazy when I told him I had a 250W halide over a 35
gallon tank. He didn't think I was so crazy after I explained that I think
a clam is a clam and a coral is a coral regardless of the size of the tank
it lives in . . .
In general I think people place too much emphasis on the gallons of the tank
or the square footage of the surface. The key questions are "What is going
to go in there" and "How can I provide the best environment for them."
Happy reefing,
Ed
Boomer
the light spectrum an any depth
1. Incident angle of light .e.g.. noon, 2 pm, 3pm etc.
2. Intensity, e.g. watts, Lux, PAR, etc.
3. Kelvin, e.g. what colors/bandwidths do we have to start with
4. Surface texture, e.g.. calm, wavy, etc.
5. Seston quality of the water, e.g., clear water , dirty water, high salinity low
salinity, DOC, POC, dyes, particles, plankton, etc.(which can change the refraction and
scattering of light allot)
". If what you said is true with the K value changes due to light angles,
shouldnt we then also see the rainow effect under the water as well? "
Yes, but you wound have to suspend the water to see it shine down on a piece of white
paper. Look at my post on the drop of water where the color bands are reversed depending
on angle. If you take a prism and shine light through it you don't see a rainbow until you
put something in from of it, like a piece of paper. The water just keeps scattering the
light. The only way of telling would be from aerial views where there would be a slight
change in coloration of the water . ****If ***we had exactly the same amount/type of light
in the morning as at noon, and we don't, you would see a color difference do to angle,
from the noon appearance to the morning appearance. It would be similar as the sky a night
being blue most of the time but at other times its red. And why does this happen, because
of a angles. And don't forget the reflection rate is different at noon than it is in the
morning.
"During this period, the K valve changes as well as intensity. Does the
change in K valve in this repsect has any effect on coral coloration"
LOL, yup this is the question and I have never seen an answer. I would bet it would,
because if the K was always say 5000k at the surface at all times of the day there would
be more blue light at all times of the day and that has to change things
"Correct. This is the part where I am pointing out the filtering out of the
higher nm ranges."
Well, of course it still gets filtered out first , BUT only on a set of ***specific
parameters*** .And you _seem_ to still miss the point . If the K is 6000K(same wattage) at
9 am and 6000K (same wattage) at noon and we measure the K value at 10 meters, they would
not be the same, because of the rules that govern reflection, refraction and the
scattering of light, due to incident angle. What you_seem_to be saying, is that with the
above example, the light, its intensity and K will be the same, be it noon or 9am at any
depth. The incident angle will change the amount of light entering the water, due to
reflection, refraction and scattering, which means at any depth there would be less light
to begin with. Since there is less light to begin with the K and intensity at any depth is
different. Light physics in water is a very complicated issue, especially in water, with
the biggest variable being Seston Quality.
Maybe you don't understand this issue. First, when talking about filtering, you need to be
careful and understand that the filtering out of light can be done in different ways and
at times there is no "filtering", but a change in the light frequency, e.g.. short wave
lengths can be change/converted to long wave lengths.
Second, you seem to think that blue light or any light is filtered out at a specific depth
and this is not so. The charts that you see, such as the one in TRA, are set to a specific
set of parameters and if those parameters (1-5 above) change so does that color chart he
has in his book change. Ask yourself the question when looking at images of coral reefs
and think blue. How come many of those images are not blue but blue-green, green or
aquamarine.When you see some of these reefs with their green color it is telling you
something, that all of the light but _green_has been filtered out , or to say it another
way the green light is going deeper than the blue light. When water is blue it is saying
all light has been absorbed but blue, which is reflecting itself back and we see a blue
reef and the same for green, red or another color. It is the same as you shirt, it is
red, because it is absorbing all colors but red which is reelecting itself back. So the
question is maybe our reef tanks should look more green than blue.Often when you see moves
of divers on reefs the most common color you see, without artificial lighting, is not
blue, but a yuck green.
One thing I haven't seen but am going to look for is a K chart vs. nm, e.g., 420 nm is
what K. For the hell of it I would like to see, or figure out, what the K is for say
aquamarine or blue green.
--
Please Join Our Growing Membership
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Boomer
WCWing@Chartermi..net
If You See Me Running You Better Catch-Up
"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:zmFt8.88881$9N1.8...@typhoon.nyc.rr.com...
: > Forget 15 m and 0, lets go with 5 m or 10 m
:
:
Jimmy Chen
> 2. Intensity, e.g. watts, Lux, PAR, etc.
> 3. Kelvin, e.g. what colors/bandwidths do we have to start with
> 4. Surface texture, e.g.. calm, wavy, etc.
> 5. Seston quality of the water, e.g., clear water , dirty water, high
salinity low
> salinity, DOC, POC, dyes, particles, plankton, etc.(which can change the
refraction and
> scattering of light allot)
> Yes, but you wound have to suspend the water to see it shine down on a
piece of white
> paper. Look at my post on the drop of water where the color bands are
reversed depending
> on angle. If you take a prism and shine light through it you don't see a
rainbow until you
> put something in from of it, like a piece of paper. The water just keeps
scattering the
> light.
I dont disagree with this statement at all. We see this kind of stuff all
the time with water vapor in the air.
> What you_seem_to be saying, is that with the
> above example, the light, its intensity and K will be the same, be it noon
or 9am at any
> depth.
Nope. What I am saying is that we know about increase in intensity as sun
approaches noon time. So assume the K valve changes, hence intensity
difference occures from morning to noon to evening. So everything you are
saying so far is true, meaning, K valve and intensity does change during the
day/season. However, if we know say 10m will filter out all of the
wavelength say 675~700nm at max intensity, and by 20m all the wavelength say
above 600nm. Then in this case, no matter how strong the intensity is for
any nm above 600nm, by the time you reach 20m none will exist. So in respect
to the K valve and its intensity, it will matter within the first 20m only
for >600nm, and for the first 10m for 675~700, using my assumed example.
How come many of those images are not blue but blue-green, green or
> aquamarine.
This is because green color (550nm) and blue color actually do pentrate
about the same at typical dive depths. Riddle has measured the ratio of
blue:green:red is 38:42:20 at 50 ft depth. So it is natural we see
aquamarine, and not just blue or "colorful".
When you see some of these reefs with their green color it is telling you
> something, that all of the light but _green_has been filtered out , or to
say it another
> way the green light is going deeper than the blue light.
Well, I dont know about green going deeper then blue. But I do agree that
green does go deeper then yellow and red.
> So the
> question is maybe our reef tanks should look more green than blue.Often
when you see moves
> of divers on reefs the most common color you see, without artificial
lighting, is not
> blue, but a yuck green.
But wont you also attribute some of this to the fact our eyes are more
sensitive to green/yellow/red then blue? According to this page,
http://www.handprint.com/HP/WCL/color1.html
Our eyes picks up 0.01 of blue intensity for every 1 green/red intensity.
> One thing I haven't seen but am going to look for is a K chart vs. nm,
e.g., 420 nm is
> what K. For the hell of it I would like to see, or figure out, what the K
is for say
> aquamarine or blue green.
LOL, good question ...
jc
Ross Bagley
Boomer <wcw...@chartermi.net> wrote:
[...snip...]
>One thing I haven't seen but am going to look for is a K chart
>vs. nm, e.g., 420 nm is what K.
First thing to realize is that color temperature (expressed in Kelvin)
describes a smooth emission spectrum, not a monochromatic source.
When we stray farther from the ideal spectrum actually described by a
color temperature, we begin to use increasingly shaky methods of
describing how to convert from the actual emission spectrum to an
equivalent color temperature
The more "jaggy" the emission plot, the worse of a problem using color
temperature to describe the source is. Compare the 50kK Iwasaki and
the 6.5kK Iwasaki bulb emission spectrum:
(about halfway down the page, the blue and orange graph)
http://www.coralreefecosystems.com/ltg_technical_data.htm
One serious peak in the blue and a lot less light overall puts the
"color temperature" of a bulb at 50kK? I believe that they have some
way of justifying their claim, but I don't believe that their bulb is
in any way representative of a 50kK emission spectrum.
Describing a 420nm laser with color temperature would convey no
useful information without also knowing your chosen way of mapping
monochromatic sources to a color temperature equivalent.
>For the hell of it I would like to
>see, or figure out, what the K is for say aquamarine or blue green.
Here are two curve generator applets for blackbody radiation:
http://csep10.phys.utk.edu/guidry/java/wien/wien.html
http://webphysics.davidson.edu/alumni/MiLee/java/bb_mjl.htm
For a 420nm peak, the color temperature is about 6.5kK. For a
420nm mean, the color temperature is about 12kK.
The Iwasaki 6.5kK bulb looks pretty darned attractive to me, both as a
decent approximator of a broad emission spectrum and as a good model
for a shallow reef in natural sunlight. the fact that they last
longer and are cheaper than the higher "temperature" bulbs is just
gravy.
Jimmy Chen
> describes a smooth emission spectrum, not a monochromatic source.
> When we stray farther from the ideal spectrum actually described by a
> color temperature, we begin to use increasingly shaky methods of
> describing how to convert from the actual emission spectrum to an
> equivalent color temperature
Interesting ... I once asked Ushio about their blue Color-Lite which
produces 465nm, and they said they cannot translate it to K temp as well. ;p
jc
Boomer
seen in the equation below. No one is arguing that.
No matter how you want to argue this, the intensity at the surface dictates what happens
with what depth, within reason
". However, if we know say 10m will filter out all of the
wavelength say 675~700nm at max intensity, and by 20m all the wavelength say
above 600nm. Then in this case, no matter how strong the intensity is for
any nm above 600nm, by the time you reach 20m none will exist"
Iz = Io x e exp -nz
" The light intensity or irradiance Iz at depth z is a function of its intensity at the
surface Io, to the log base of the neg extinction coefficient n at depth distance, z, in
meters."
More below
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: How come many of those images are not blue but blue-green, green or
: > aquamarine.
:
: This is because green color (550nm) and blue color actually do pentrate
: about the same at typical dive depths. Riddle has measured the ratio of
: blue:green:red is 38:42:20 at 50 ft depth. So it is natural we see
: aquamarine, and not just blue or "colorful".
Yup, I know that, just wanted to see where you would go, call it a small troll. The colors
left are a mix, yielding the aquamarine
But it is still telling you how important green light is and we are getting beat to death
with more blue, more blue. Take note that Danna shows more green than blue
:
: When you see some of these reefs with their green color it is telling you
: > something, that all of the light but _green_has been filtered out , or to
: say it another
: > way the green light is going deeper than the blue light.
:
: Well, I dont know about green going deeper then blue. But I do agree that
: green does go deeper then yellow and red.
Well, it does, depending on how you want to look at it. The Seston qaulaity of the water
controls this. There are lakes that are, blue, green, borwn and even red, as the other
colors are filtered out, do to the different Seston ( things in the water, that filter the
light ). Thus, only red light is left to contiune down, as it is not filtered out, which
would be a short distance of course. So in such cases it goes deeper than blue
:
: > So the
: > question is maybe our reef tanks should look more green than blue.Often
: when you see moves
: > of divers on reefs the most common color you see, without artificial
: lighting, is not
: > blue, but a yuck green.
:
: But wont you also attribute some of this to the fact our eyes are more
To a small amount, but just look at Danna's data, or any other data, more green
We are the most sensative to 520 nm. Also jc, it is just not out eyes, light meters are
also based on our eyes and don't see blue light good, so their reading is always a
question, at least to a degree
: sensitive to green/yellow/red then blue? According to this page,
:
:
Boomer
"The Iwasaki 6.5kK bulb looks pretty darned attractive to me, both as a
decent approximator of a broad emission spectrum and as a good model
for a shallow reef in natural sunlight. the fact that they last
longer and are cheaper than the higher "temperature" bulbs is just
gravy."
Glad you like the bulb I introduced to this hobby over about ten years ago. Many still
think to seem it rules
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"Ross Bagley" <r...@jump.net> wrote in message news:_OFu8.7446$sj6.599868@news20...
: In article <ubm5ija...@corp.supernews.com>,
Boomer
regards to the equation I posted, known as Beer's Law. I also have it programmed into my
calculator. This is in guards to this remark below, which is not so. It is telling you
that the higher the intensity at the surface the farther light goes plus some other
remarks I commented on.
"no matter how strong the intensity is for
any nm above 600nm, by the time you reach 20m none will exist"
http://www.oceansonline.com/light_in_the_sea.htm
Take his example if 1500 microEinsteins, if you click on "Click here to view a
completed table and get answers to these questions."
There is a table with the answers at the bottom of the page........ BUT, lets take things
to a extreme (you like to do that :-) ), first take note that at 200 m there is only 24.47
microEinsteins of intensity left at 200 m
So, if we change Io to say 100,000 microEinsteins there is still an intensity of 1831.56
at 200 m and if we go to 300 m it is 247. 87 . Now if we change the Io to 1,000,000
microEinsteins the intensity at 400 m is 335.46 microEinsteins
So you see light is not 0 at some set depth, as I have been trying to say you have to look
at the parameters. If we had 2 suns out there that diagram in Julian's book would show
light going to a greater depth, or for that matter the one on this link. However, we don't
have two suns or light at the surface of 250,000 lux, so the rule follows what we have and
get a chart like this link or Julian's book, which_allows_us to say there is no light at
this depth (20m), be it blue, red, pink or otherwise. And Beer's law can be extened to
caclulate a nm wave length.
Jimmy Chen
Good link ... Gives a more detail explaination about water "quality".
> There is a table with the answers at the bottom of the page........ BUT,
lets take things
> to a extreme (you like to do that :-) ), first take note that at 200 m
there is only 24.47
> microEinsteins of intensity left at 200 m
Right. My question here is how did he derived that k for his attenuation
coefficient? It seems like just a valve he plugs in. Even in his own article
he indicated the euphotic zone typically around 150M in clear waters. When
we take that plus the fact the sun's max uM is ~2100, the k is going to be
higher then 0.02, or even the 0.04 in his examples.
> So, if we change Io to say 100,000 microEinsteins there is still an
intensity of 1831.56
> at 200 m and if we go to 300 m it is 247. 87 . Now if we change the Io to
1,000,000
> microEinsteins the intensity at 400 m is 335.46 microEinsteins
In theory, yes, this is the number you will get. But in real life the uE
will not be much higher then 2100. Following TRA is also indiactes tropical
waters seems to have the euphotic zone at 100m.
jc
Jimmy Chen
Boomer,
I have a question now ... I plugged in the Beer's law and some actual
measurements from Dana Riddle of Honaunau, Hawaii. The figures dont jive ...
According to Dana's numbers his reading is (in feet and uMols)
Surface = 2100
1.00 = 1500
12 = 1200
20 = 1000
63 = 400
100 = 240
But when I plug in the Beer's Law using 2100 uMols, I get the following ...
ft/k 0.07 0.09 0.12 0.15 1.1
1 2056 2043 2025 2006 1501
12 1626 1511 1354 1213 38
20 1371 1213 1010 842 3
60 584 405 234 135 0
100 249 135 54 22 0
So to match Dana's readings, I had to use 0.07 for 100 ft, 0.09 for 63 ft,
0.12 for 20 ft, 0.15 for 12 ft, and 1.1 for 1 ft. But as you can see, this
totally changes the euphotic zone. Am I doing something wrong or something
just isnt right with this law?
jc
Boomer
Beer's Law http://www.shu.ac.uk/schools/sci/chem/tutorials/molspec/beers1.htm &
http://www.cofc.edu/~deavorj/521/beerslaw.html
"When
we take that plus the fact the sun's max uM is ~2100, the k is going to be
higher then 0.02, or even the 0.04 in his examples."
You don't understand this because you only have peices with blank spots in between
You would have to read Smith & Baker, 1981 or a have a copy of
Light and Photosynthesis in Aqautic Ecosytems, J.T.O. Kirk
As far as k goes, he is giving you a rounded off k or avg. for some shorter wave lengths.
As I said you can do this for any wave length, eg.g 420 nm = .0153, 500nm =.0257, 520
=.0477 and 600 nm= .224
Calcualting k jc is a place we don't want to go, for we both will be brought to a new
kinda La-La-Land
"In theory, yes, this is the number you will get"
This Law is not theory jc, it is a factual law and in pure water it produces a straight
log line
"TRA is also indiactes tropical
waters seems to have the euphotic zone at 100m."
This is somewhat incorrect
The sunlit layer from the surface to the depth of 1% light level wherein most of the
primary productivity takes place is called the Euphotic Zone. The depth varies
geographically and seasonally and can range from a few meters in turbid, highly productive
waters near the shore to around 200 m in tropical waters. The ocean average is around 100
m. It is a zone with sharp gradients in illumination, temperature and salinity, and
overlies the aphotic zone. It is also known as the photic zone.
--
Jimmy Chen
shorter wave lengths.
> As I said you can do this for any wave length, eg.g 420 nm = .0153, 500nm
=.0257, 520
> =.0477 and 600 nm= .224
So in order for the Beer Law to work, it should only applied to one
wavelength with its associated k valves, and not the full spectrum and the
filtering factor of different parts of the ocean?
> This Law is not theory jc, it is a factual law and in pure water it
produces a straight
> log line
Right, but we arent talking about pure water. Supposely the k valve is that
non-pure water factor, isnt it?
jc
Boomer
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:KNYu8.129208$in3.34...@typhoon.nyc.rr.com...
: > As far as k goes, he is giving you a rounded off k or avg. for some
: shorter wave lengths.
: > As I said you can do this for any wave length, eg.g 420 nm = .0153, 500nm
: =.0257, 520
: > =.0477 and 600 nm= .224
:
: So in order for the Beer Law to work, it should only applied to one
: wavelength with its associated k valves, and not the full spectrum and the
: filtering factor of different parts of the ocean?
Yes jc, you have that right> I think some guys try to take an average of the K and use
that as a general value
:
: > This Law is not theory jc, it is a factual law and in pure water it
: produces a straight
: > log line
:
: Right, but we arent talking about pure water. Supposely the k valve is that
In non pure water things get very, very complicated, because of the Seston value and
trying to take a column of natural seawater would almost be a waste as it can change
yearly, monthly , daily, hourly, so the best we can do is a chart similar to Julian's or
the one in the link, a general chart, close enough for us and simple explanation. You have
to look at it this way, we can only really use pure water to get a accurate value with
simpliciy, just like meaursuring 02 in water kinda, as salinity, pressure, temperature,
aagitation rate can make a dif. And this issue of K is much, much worse. In order to do it
in non-pure water, it has been done, you have to make corecctions of the paramaters, like
for example the water is saturated with CaCO3 and thus a whole new set of K, OK, now lwets
throow in some plankton and how much plankton, POC, DOC, now we have a mess
: non-pure water factor, isnt it?
:
: jc
:
:
Boomer
and remember parameters, parameters. Are there k's for Dana's data that he did, if not you
will not get a correct answer. What is the Seston of your K's and what was the Seston of
Danna's column of water, e.g. what time of the day, surface turbulence, Kelvin, etc..
Dana's values are just 2100 uMols decreased to an x depth and the k's you are using are
for a nm wave length, .07 is about 555 nm and your 1.1 is about 705 nm in distilled water.
You need k's for his water, at the exact spot he took the measurements and under the exact
conditions and then you have to make corrections for all the shit in the water or anything
that can alter the k, to get the correct answer to jive with Dana's data and it will jive
The law is fine, been proven many'a times, once you know all the parameters and correct
for them, which is what I meant by La-La-Land, very, very complicate math. We are now at a
point where we are way the f*&*^ over our heads. If you search the lit or have books or
some articles like I do you will see dif k's for a nm wave length as the conditions for
those k's are dif. Because it is such a complicate issue figuring k's for any column of
non-pure water you almost only see those of distilled water, so one gets an idea of how
light decrease with depth and how it can be expressed as simple a mathematically
expression
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"Jimmy Chen" <ji...@reefkeepers.DOTorg> wrote in message
news:7GXu8.128979$in3.34...@typhoon.nyc.rr.com...
: > the equation I posted, known as Beer's Law.
:
:
Jimmy Chen
are using are
> for a nm wave length, .07 is about 555 nm and your 1.1 is about 705 nm in
distilled water.
His values are actual measurements using a PAR meter. I was just trying to
use the Beer's law and see where it would fit. After you explain above that
the k really only works for a given nm and it changes according to that
explains why the difference. It shouldnt really be used what I was doing.
> You need k's for his water, at the exact spot he took the measurements and
under the exact
> conditions and then you have to make corrections for all the shit in the
water or anything
> that can alter the k, to get the correct answer to jive with Dana's data
and it will jive
> The law is fine, been proven many'a times, once you know all the
parameters and correct
> for them, which is what I meant by La-La-Land, very, very complicate math.
We are now at a
> point where we are way the f*&*^ over our heads.
Understand. This also means when doing something like this, it is almost a
calculus function where k is a changing value, rather then k being a
constant as the url you pointed me to explained it.
jc
Ted Kunich
years... you have to go and bring that up again????? ACK!!! ;)
T
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> years... you have to go and bring that up again????? ACK!!! ;)
LOL Ted, and you thaw they were useless ... Me too. ;p
jc