Mixing Kalkwasser
Jennings Heilig
Hold the phone! Now I'm supposed to be stirring my Kalkwasser?? I was
told to mix it, let it sit for several hours, then use it. I was told to
leave the precipitate in the bottom and not use it! Now I'm told to stir
it? What gives?
Jennings
JEFF PFOHL
: Hold the phone! Now I'm supposed to be stirring my Kalkwasser?? I was
: told to mix it, let it sit for several hours, then use it. I was told to
: leave the precipitate in the bottom and not use it! Now I'm told to stir
: it? What gives?
It depends on what your system needs. For most systems the standard
procedure is to mix kalkwasser to a saturated state. Let it sit
overnight so the kalk settles to the bottom. Decant the clear liquid
off the top leaving the powder behind. Use this clear solution to dose
your tank. Some people have found that their systems require more Ca
then this system provides. They thus use "milky" kalkwasser. They mix
the solution but instead of pouring off the clear liquid they pull
kalkwasser from the mixing jar keeping the kalk suspended. This is a
very strong kalk solution. DON'T try it unless you have a pH meter and
have an idea of what your system needs especially what you are
doing. You can easily spike your pH to dangerous levels, strip the
alkalinity and Ca out of the water (the opposite of what you are
trying to accomplish) and basically make a mess of your tank. The 3rd
method is very similar to the 2nd method and that involves a
kalkwasser reactor. Read posts on this topic and see the discussion in
Delbeek and Sprung's "The Reef Aquarium" for more details. Many
informative posts are archived in Fish/Reefs/kalkwasser
Fish/Hardware/careactors
--
JEFF PFOHL
E-MAIL: PF...@NUCALF.PHYSICS.FSU.EDU
PHONE : (904) 644-1598 work
(904) 224-0707 home
(904) 644-9848 fax
NEW and IMPROVED: http://nucalf.physics.fsu.edu/pfohl
"I will shoulder more than my share of the task, whatever it may be.
100% and then some!"
Steve Allen in HB
>
>
>
> Hold the phone! Now I'm supposed to be stirring my Kalkwasser?? I was
> told to mix it, let it sit for several hours, then use it. I was told to
> leave the precipitate in the bottom and not use it! Now I'm told to stir
> it? What gives?
>
No you should not stir Kalkwasser. If someone told you to, they are wrong.
Steve Allen
<>-< <>-<
Craig Bingman
Jennings Heilig <jhe...@gate.net> wrote:
>
>
>Hold the phone! Now I'm supposed to be stirring my Kalkwasser?? I was
>told to mix it, let it sit for several hours, then use it. I was told to
>leave the precipitate in the bottom and not use it! Now I'm told to stir
>it? What gives?
Most people use clear limewater, the protocol to make that is put 1-2
tbsp of calcium hydroxide or calcium oxide per gallon into a container of
water, use a powerhead to stir it (preferably while covered, get the cord
through the lid as best you can) and then let the solution settle for
several hours, until water-clear. Then use it.
If your goal is phosphate rejection, then you need to be more careful
about how you handle it. You should prepare as above, then siphon into a
second container, and take extreme care not to get any of the precipitate
or surface scum into the aquarium. Both the sludge at the bottom and
surface scum hold phosphate, if phosphate is present in the water you use
to make the limewater.
If you do it right, you can take starting water with 1+ ppm phosphate,
and reduce that to 0.01 ppm phosphate overnight. If you are able to
dispense the limewater without ever getting into the sludge at the
bottom, you may well be able achieve good phosphate rejection without
siphoning it into a second container. Just be damn sure that you never
stir up the sludge in the bottom when dispensing the product.
There will be an article on this in the next issue of AF, with data
shown, more detail, etc. The most important issue was how the limewater
was stirred. If you just give it a quick shake, it does not work nearly
as well as when you stir it with a powerhead for 30+ minutes, then let it
settle.
As far as dispensing milky limewater... that is risky business, even if
the input water is phosphate free (and you should Never use milky
limewater if the water you use is phosphate contaminated.)
Supersaturated limewater has an enormous demand for carbon dioxide, much
greater than most aquaria can provide unless they have a CO2 dosing
system.
Indeed, for some aquaria, saturated limewater may have too high a CO2
demand. Some people are trying way too hard, and the would get more out
of less... half-saturated limewater might work better for them than the
fully saturated product. It gets dicey to reject phosphate at less than
full-strength, and you should not blend phosphate-bearing water with
saturated limewater. The precipitation kinetics are dependent on how you
stir the limewater when you mix it in the first place, and precipitation
will be slow, much slower, if you go this way.
Craig
Nigel Jolley
and disadvantages.
You need to mix/ stir the calcium hydroxide very well to get it
to dissolve in water. If you do and let it settle you can get a
saturated solution with a calcium level between 800 and 1000 ppm
calcium depending on temperature and how well you did it. You can
add the clear liquid at night to your tank using one of the many
gravity fed drip methods or a dosing pump. If you do this slowly
(drip by drip) there will be only a small rise in pH. The problem
is that if you mix a lot fo KW this way and keep it carelessly the
calcium level can drop substantially. The other problem is that
many people with high calcium usage find that using clear KW does
not provide enough calcium into the tank.
The alternative to this is to add a cloudy suspension of calcium
hydroxide to your tank. This allow much more calcium to be added
per litre of water. To keep the calcium hydoxide suspended it must
be stired continuously. There are dangers involved in doing it this
way. firstly it is easy to get very large and catestrophic pH
rises. secondly adding the suspension too rapidly causes can cause
a chemical reaction in the tank that actually removes dissolved
calcium ions and reduces the alkalinity in the tank. This can be
over come by adding CO2 as well as KW but the message is you need
to know what your doing and be carefull.
I hope this helps.
nej
Braden N. McDaniel
>Jennings Heilig <jhe...@gate.net> wrote:
>> Hold the phone! Now I'm supposed to be stirring my Kalkwasser?? I was
>> told to mix it, let it sit for several hours, then use it. I was told to
>> leave the precipitate in the bottom and not use it! Now I'm told to stir
>> it? What gives?
>>
>
>
>No you should not stir Kalkwasser. If someone told you to, they are wrong.
Steve, I suggest you familiarize yourself with designs the likes of that
Nilsen published in -FAMA- in 1992. This "kalkwasser reactor" uses a magnetic
stir bar to constantly stir the mixture. The stirring is slow enough that the
top layer of water should have very little particulate matter in it, and it is
from this area that the water is fed to the tank. A surplus of Ca(OH)2 is kept
in the chamber such that the chamber can be fed automatically from a reservoir
of distilled water, and and additions of Ca(OH)2 can be made manually on a
less demanding schedule.
Braden
Steve Allen in HB
Braden,
My post may have been a little short, but was to the point. If the original poster
had this device he never would have ask the question...maybe.
If mixing KW in a container you do not want to stir the sediment in the bottom. You
should however, siphon the clear mixture of of the top. Oh yeah avoid the surface scum.
Steve Allen
<>-< <>-<