KH/pH/Co2 relationship
Tauni Sandy
(http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm) and figure my
CO2 is about 6ppm, based on the pH and KH. I'm not sure that figure is
to be trusted, since I add crushed coral to my tank to raise the KH to
about 5 and the pH to about 7.4 (tap water KH is 2 and pH is 7.0) I am
raising platties.
Anyway, I read his page again and again, but I can't understand the part
about what happens when you add stuff that changes the KH & pH. I'm
currently not adding CO2, except possibly in the form of Seachem
Flourish Excel (1 ml/day unless I forget). I'm currently fertilizing
with .25 ml/day of TMG. Light is 30 watts on this 10 gallon tank. I am
contemplating DIY CO2, but I'm giving Flourish Excel a chance, since I
bought the bottle :-)
I ran all my tests Thursday:
pH=7.2 (now 7.4 since I added more coral)
KH=2 (now 5 since I added more coral)
NH3=0
NO2=0
NO3=0
Fe=0,0 (both iron tests in Hagen kit)
PO4=0
If this keeps up I suppose I'll have to add nitrogen too. Is that KNO3?
Right now there are only 3 platties in there and a few snails and 2
Amano shrimp. It may be irrelevant, but the duckweed is doing great. It
doubled in 4 days! (The surface was covered 5 days ago, so I removed
half, and it was covered again yesterday). Is it using the nitrogen
before the other plants can get it?
Wishing I'd paid attention in Limnology, although I supposed I could dig
out my copy of Wetzel...
Tauni
James Purchase
> (http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm) and figure my
> CO2 is about 6ppm, based on the pH and KH. I'm not sure that figure is
> to be trusted, since I add crushed coral to my tank to raise the KH to
> about 5 and the pH to about 7.4 (tap water KH is 2 and pH is 7.0) I am
> raising platties.
If the buffer system in your water is carbonate-bicarbonate based (and
crushed coral is compatible with that), then the tables are "accurate
enough". The usual thing which can throw them off is when someone uses a
buffer which relies on phosphates (fine for a fish only tank, not so good in
a planted tank). One thing you should be aware of when using the chart is
that how closely your can guesstimate the CO2 concentration is highly
dependent on how accurate your readings of both KH and pH are. You should be
able to accurately measure your pH to at least 0.2 units (0.1 is even
better). Trying to use a kit which only reads to 0.5 units almost becomes
pointless when trying to read the chart..
> Anyway, I read his page again and again, but I can't understand the part
> about what happens when you add stuff that changes the KH & pH. I'm
> currently not adding CO2, except possibly in the form of Seachem
> Flourish Excel (1 ml/day unless I forget). I'm currently fertilizing
> with .25 ml/day of TMG. Light is 30 watts on this 10 gallon tank. I am
> contemplating DIY CO2, but I'm giving Flourish Excel a chance, since I
> bought the bottle :-)
If you are NOT adding supplemental CO2 (either from DIY yeast or compressed
gas), don't worry about your CO2 concentration - because its going to be low
anyway. Don't think that by messing with either KH or pH that you will
increase the available CO2 - it doesn't work that way. The only way to
increase the CO2 concentration in the water column is by adding CO2. What
you can do in that situation is to minimize surface turbulance (which would
hasten the departure of CO2 from the water). Excel is a viable alternative
for small tanks wihtout injected CO2 but can also be effective once you
start adding "real" CO2. The biggest problem with adding CO2 to a small tank
is that it can cause your plants to outgrow the available space _really_
quickly. You'd have to prune regularly and religiously. It _is_ quite
possible to grow plants without adding CO2.
> I ran all my tests Thursday:
> pH=7.2 (now 7.4 since I added more coral)
> KH=2 (now 5 since I added more coral)
> NH3=0
> NO2=0
> NO3=0
> Fe=0,0 (both iron tests in Hagen kit)
> PO4=0
>
> If this keeps up I suppose I'll have to add nitrogen too. Is that KNO3?
> Right now there are only 3 platties in there and a few snails and 2
> Amano shrimp. It may be irrelevant, but the duckweed is doing great. It
> doubled in 4 days! (The surface was covered 5 days ago, so I removed
> half, and it was covered again yesterday). Is it using the nitrogen
> before the other plants can get it?
Duckweed will usually melt away to nothing in a tank without available
nitrogen sources - just because you can't measure it doesn't mean that it
isn't there - the duckweed might be sucking it up as fast as it is
introduced/produced. TMG is mainly a source for trace elements - the macro
elements are expected to come from fish food (that's the theory anyway). If
you have some KNO3, you could mix some up (follow the PMDD instructions) and
dose it gradually. The plants will probably greatly benefit from the extra
K.
What other plants do you have?
> Wishing I'd paid attention in Limnology, although I supposed I could dig
> out my copy of Wetzel...
If you have a copy of Dr. Robert Wetzel's book on Limnology, sit down and
read it, cover to cover. There is a lot that isn't directly applicable to
aquariums, but it is the best overall backgrounder for any f/w aquarist - it
will help you understand the things that happen in a body of freshwater that
contains living organisms. Well worth the effort.
If you're not quite up to Wetzel, Chuck's web site has a lot of very good
information presented well.
James Purchase
Toronto
Tauni Sandy
> If the buffer system in your water is carbonate-bicarbonate based (and
> crushed coral is compatible with that), then the tables are "accurate
> enough".
Ok, good :-)
> One thing you should be aware of when using the chart is
> that how closely your can guesstimate the CO2 concentration is highly
> dependent on how accurate your readings of both KH and pH are. You should be
> able to accurately measure your pH to at least 0.2 units (0.1 is even
> better). Trying to use a kit which only reads to 0.5 units almost becomes
> pointless when trying to read the chart..
I use 2 different pH tests (Wardley's and Aquarium Pharmeceuticals) just
to double check sometimes and find they read the same and both are to
the .2 unit.
> If you are NOT adding supplemental CO2 (either from DIY yeast or compressed
> gas), don't worry about your CO2 concentration - because its going to be low
> anyway.
It was more an idle curiousity than a worry. I'm wondering if the
Flourish Excel is increasing the CO2 in ways I can detect or simply
having some other effect. I've noticed that the algae that plagued me
when I added the extra 15 watts is almost gone.
> Don't think that by messing with either KH or pH that you will
> increase the available CO2 - it doesn't work that way.
I understood that much. I added the coral because platties are supposed
to prefer harder and more alkaline water. Mine comes out of the tap at
pH 7.0 and KH 1 or 2. I also wanted to increase the buffering in case
the Excel was actually increasing CO2 in my tank.
> The biggest problem with adding CO2 to a small tank
> is that it can cause your plants to outgrow the available space _really_
> quickly. You'd have to prune regularly and religiously. It _is_ quite
> possible to grow plants without adding CO2.
>
Yeah, I know I can do without CO2. I just wanted them to grow faster so
I can fill up the tank with plants. I also like the look of the tank
with more light. More light seems to necessitate some carbon source, or
so I hear. I know that algae is not doing well in my tank anymore :-) If
I added CO2 (such as a DIY bottle) I would probably want to make a weak
batch and maybe even stop it once the tank gets that "heavily planted"
look. I don't mind pruning and propagating to get there, I just don't
want to spend more money on buying plants.
> Duckweed will usually melt away to nothing in a tank without available
> nitrogen sources - just because you can't measure it doesn't mean that it
> isn't there - the duckweed might be sucking it up as fast as it is
> introduced/produced. TMG is mainly a source for trace elements - the macro
> elements are expected to come from fish food (that's the theory anyway). If
> you have some KNO3, you could mix some up (follow the PMDD instructions) and
> dose it gradually. The plants will probably greatly benefit from the extra
> K.
>
Where could I find some KNO3? I know TMG is just micro nutrients, but I
always assumed my fish would make enough nitrogen. I could bring another
couple platties from the other tank.
> What other plants do you have?
Crypts (wendtii), Hygro (green & red), Cabomba, Java Fern, and hornwart.
> If you have a copy of Dr. Robert Wetzel's book on Limnology, sit down and
> read it, cover to cover. There is a lot that isn't directly applicable to
> aquariums, but it is the best overall backgrounder for any f/w aquarist - it
> will help you understand the things that happen in a body of freshwater that
> contains living organisms. Well worth the effort.
>
> If you're not quite up to Wetzel, Chuck's web site has a lot of very good
> information presented well.
I wasn't up to Wetzel the first time I took Limnology, which is part of
the reason I failed. With a lot of help from my husband (who is not a
science person, just a smart guy) I passed on the second try. I've read
(and continue to read) Chuck's site and find it a very helpful
reference. I'll open Walstad's book before I go braving the spider
infested closets to dig out Wetzel :-)
Thanks for your reply. You've cleared up some things for me.
Tauni
James Purchase
> > that how closely your can guesstimate the CO2 concentration is highly
> > dependent on how accurate your readings of both KH and pH are. You
should be
> > able to accurately measure your pH to at least 0.2 units (0.1 is even
> > better). Trying to use a kit which only reads to 0.5 units almost
becomes
> > pointless when trying to read the chart..
>
> I use 2 different pH tests (Wardley's and Aquarium Pharmeceuticals) just
> to double check sometimes and find they read the same and both are to
> the .2 unit.
Do you know if they are using the same indicator solution? They may just be
repackaged varsions of the same thing, but doing two separate tests and
comparing the results can help even out any possible errors you might make
(not saying that you are making them, its just that having two vials to
compare gives you more confidence in the results). I'm not familiar with
either kit, I use a LaMotte pH kit which measures to 0.2. With it, I find
that I can usually extrapolate down to 0.1 (but that's only in good light
and with well rested eyes).
> > If you are NOT adding supplemental CO2 (either from DIY yeast or
compressed
> > gas), don't worry about your CO2 concentration - because its going to be
low
> > anyway.
>
> It was more an idle curiousity than a worry. I'm wondering if the
> Flourish Excel is increasing the CO2 in ways I can detect or simply
> having some other effect. I've noticed that the algae that plagued me
> when I added the extra 15 watts is almost gone.
Excel is not CO2, but it does contain carbon compounds which plants can get
at and use to the same effect (or so I've been told by Seachem). It works in
the few tanks I've used it on and if you've found it working in yours, then
its obviously a good idea to continue its use. Just don't overdose it.
> > Don't think that by messing with either KH or pH that you will
> > increase the available CO2 - it doesn't work that way.
>
> I understood that much. I added the coral because platties are supposed
> to prefer harder and more alkaline water. Mine comes out of the tap at
> pH 7.0 and KH 1 or 2. I also wanted to increase the buffering in case
> the Excel was actually increasing CO2 in my tank.
Are your platies the regular X. maculatus or X. variatus varieties found in
the trade, or are they "species"? The regular, tank raised platies are so
popular because they are adaptable and accomodating - they will happily live
and breed (like bunnies) under a wide variety of water conditions. You would
rarely have to do anything special to your water just to accomodate their
needs (other than to change a portion of it regularly). But increasing KH up
a bit from what you have in your tap water is a good idea anyway, becuase
you just lessen any possibility of "pH crash" which can be caused by a
buildup or organic acids in the tank as well as by the addition of CO2
(which acts as an inorganic acid in water). Six of one, half a dozen of the
other - adding crushed coral to water such as yours offers a controlable way
of doing what you want to do.
> > The biggest problem with adding CO2 to a small tank
> > is that it can cause your plants to outgrow the available space _really_
> > quickly. You'd have to prune regularly and religiously. It _is_ quite
> > possible to grow plants without adding CO2.
> >
> Yeah, I know I can do without CO2. I just wanted them to grow faster so
> I can fill up the tank with plants. I also like the look of the tank
> with more light. More light seems to necessitate some carbon source, or
> so I hear. I know that algae is not doing well in my tank anymore :-) If
> I added CO2 (such as a DIY bottle) I would probably want to make a weak
> batch and maybe even stop it once the tank gets that "heavily planted"
> look. I don't mind pruning and propagating to get there, I just don't
> want to spend more money on buying plants.
More light DOES mean that there is an increased need for CO2 - you can think
of light as the engine which drives your tank - run it faster and everything
runs a bit faster and requires a bit more of all nutrients. If your plants
are doing well (and the algae you had before is disappearing) using the
Excel, then you're ok.
Your plants will fill in, it just might take more time for them to do it
than in a CO2 injected tank (CO2 + high light can send a tank into
overdrive, an area where you have to be very careful about nutrient levels
and maintenance. Such tanks can be magnificient but they can also be a lot
more work.)
> Where could I find some KNO3? I know TMG is just micro nutrients, but I
> always assumed my fish would make enough nitrogen. I could bring another
> couple platties from the other tank.
The most readily available source of KNO3 is Stump Remover from either a
good hardware store or a local garden center. You have to make sure that it
is pure KNO3 however as not all "stump removers" are. Check the KRIB for
details.
Depending upon the fish and the food they eat (and subsequent wastes that
they produce) is the traditional "fish tank" approach to growing a few
plants. It does work, to a degree (heck, it worked for me for years), but
when you crank up the light, you can find a need for supplementation.
> > What other plants do you have?
>
> Crypts (wendtii), Hygro (green & red), Cabomba, Java Fern, and hornwart.
I've always found Cabomba to be a hard nut to crack - sometimes it grows,
sometimes it just falls apart. A similar looking plant is Ambulia
(Limnophila) which grows beautifully, both with and without extra CO2. It
has the added benefit of acting like an "indicator" for nutrient levels --
if the growing tips get pale, you need more nutrients. But none of the
plants you have is difficult and both the Crypts and Java fern can and will
increase in both size and number over time.
>
> I wasn't up to Wetzel the first time I took Limnology, which is part of
> the reason I failed. With a lot of help from my husband (who is not a
> science person, just a smart guy) I passed on the second try. I've read
> (and continue to read) Chuck's site and find it a very helpful
> reference. I'll open Walstad's book before I go braving the spider
> infested closets to dig out Wetzel :-)
Oh, if you have a copy of Diana's book, by all means go for it. Her's is one
of the best books available for the type of tank you are trying to maintain
(non-CO2 injected). Pretty much everything in Walstad is directly related to
use in an aquarium.
James Purchase
Toronto
Tauni Sandy
> > I use 2 different pH tests (Wardley's and Aquarium Pharmeceuticals) just
> > to double check sometimes and find they read the same and both are to
> > the .2 unit.
>
> Do you know if they are using the same indicator solution?
I have no idea :-)
> Are your platies the regular X. maculatus or X. variatus varieties found in
> the trade, or are they "species"?
This 10 gallon tank has X. variatus, the male looks a lot like the
Peacock Variatus in the Axelrod & Wischnath's book. I don't think
they're very picky about water, which is why I stopped routinely adding
salt. I just wanted the water harder so I can add CO2 if I choose to.
> Your plants will fill in, it just might take more time for them to do it
> than in a CO2 injected tank (CO2 + high light can send a tank into
> overdrive, an area where you have to be very careful about nutrient levels
> and maintenance. Such tanks can be magnificient but they can also be a lot
> more work.)
>
I have been thinking about this and I think today I will make up a DIY
bottle. I'll keep up with the nutrient needs and maintenance. Does
anyone forsee major problems if I use CO2 to fill out the tank with
plants, then switch to Excel?
> I've always found Cabomba to be a hard nut to crack - sometimes it grows,
> sometimes it just falls apart.
My Cabomba is doing great, in both tanks :-) Sometimes the hornwort
falls apart a little, apparently when the water gets too soft.
> Oh, if you have a copy of Diana's book, by all means go for it. Her's is one
> of the best books available for the type of tank you are trying to maintain
> (non-CO2 injected). Pretty much everything in Walstad is directly related to
> use in an aquarium.
>
I have 2 tanks, one is this 10 gallon I've been tinkering with. The
other is a 25 gallon hexagon that I set up right after reading Walstad.
It's got soil under gravel and is located near the window. The plants
are doing great in there too. I'm not adding CO2 or Excel or anything
besides fish food. I do make (almost) daily 10% water changes, since I
have fry in there. Almost no algae in there either. That's my "natural"
tank, the 10 gallon is my "tinkering" tank :-)
Tauni
Alex R
news:1f2uuxa.1l7i6n4j6pzusN%wugg...@yahoo.com...
> James Purchase <jppur...@Home.com> wrote:
>
> > > I use 2 different pH tests (Wardley's and Aquarium Pharmeceuticals)
just
> > > to double check sometimes and find they read the same and both are to
> > > the .2 unit.
> >
> > Do you know if they are using the same indicator solution?
>
> I have no idea :-)
The AP 6.0-7.6 pH test kit uses bromothymol blue solution. And I bet the
Wardley's does too. It's probably the most common, if not the only, solution
for this pH range in inexpensive test kits. But two test kits using the same
reagent may not give the same color in the test tube for the same sample.
For example, I compared the test tube color of an older AP kit and a newer
one and found that they were not exactly the same, though the results were,
using their respective color charts.
___
Alex
pcalex@-yahoo.com
Remove the - when replying by email.
James Purchase
> Peacock Variatus in the Axelrod & Wischnath's book. I don't think
> they're very picky about water, which is why I stopped routinely adding
> salt. I just wanted the water harder so I can add CO2 if I choose to.
You know, for all the exotic and rare new species which have beenin
introduced into the hobby over the last 10 or 15 years, it is STILL really
hard to beat the various livebearer species. Years ago, the quality of the
different tank bred varieties was quite a bit higher than what is generally
available today but there are still a few dedicated breeders who are trying
to bring them back.
> > Your plants will fill in, it just might take more time for them to do it
> > than in a CO2 injected tank (CO2 + high light can send a tank into
> > overdrive, an area where you have to be very careful about nutrient
levels
> > and maintenance. Such tanks can be magnificient but they can also be a
lot
> > more work.)
> >
> I have been thinking about this and I think today I will make up a DIY
> bottle. I'll keep up with the nutrient needs and maintenance. Does
> anyone forsee major problems if I use CO2 to fill out the tank with
> plants, then switch to Excel?
No, you shouldn't see any problems - if you do, you can always just mix up
another batch of yeast. The only "effect" I would expect is a slowdown of
growth once you remove the additional CO2. In a 10 gallong tank, the
"slowdown" might be a good thing.
> > I've always found Cabomba to be a hard nut to crack - sometimes it
grows,
> > sometimes it just falls apart.
>
> My Cabomba is doing great, in both tanks :-) Sometimes the hornwort
> falls apart a little, apparently when the water gets too soft.
Yes, hornwort does better in hard water. It can obtain its Caron needs from
bicarbonates in the water.
> > Oh, if you have a copy of Diana's book, by all means go for it. Her's is
one
> > of the best books available for the type of tank you are trying to
maintain
> > (non-CO2 injected). Pretty much everything in Walstad is directly
related to
> > use in an aquarium.
> >
> I have 2 tanks, one is this 10 gallon I've been tinkering with. The
> other is a 25 gallon hexagon that I set up right after reading Walstad.
> It's got soil under gravel and is located near the window. The plants
> are doing great in there too. I'm not adding CO2 or Excel or anything
> besides fish food. I do make (almost) daily 10% water changes, since I
> have fry in there. Almost no algae in there either. That's my "natural"
> tank, the 10 gallon is my "tinkering" tank :-)
The success of Walstad's approach depends to a large part to the presence of
soil in the substrate. The mass of soil acts as a resevoir of all sorts of
nutrients for use by the plants. Some plants have the ability to obtain
their carbon needs through their roots and decomposition of organic material
in the substrate can supply this. Since you have soft water, it is important
that you watch what Walstad calls the "hardwater nutrients" - Ca, Mg and K.
Since your soft water is probably deficient in these minerals, it is
important that you add them somehow - either in the soil or by using crushed
coral as you have been doing. Some soils have enough, others don't. If you
can cope with some more reading, you might want to check out the material
Steve Pushak has on his web site regarding soil substrates
(http://home.infinet.net/teban/index.html). A few years ago, I set up a tank
following Steve's methods and it produced some specacular results with no
algae problems at all.
James Purchase
Toronto