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Old 10-03-2006, 05:18 PM
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Originally Posted by bklynreef View Post
solbby, You just totally said what I have been leading up too for a long time. from what I have been hearing and what I have learned on my own has been the same that ca and co reactors will not do what the the 2 part supplement can do and much better. my only problem is that with a system that is 1000 gallons, what would be more economical? I would love to not have to deal with 2 reactors and two more things that can fail. most of the experts have been saying to just keep it simple. dosing is better than all the reactors in the world and more acurate and foolproof.
looks like in the meantime i just may go without any reactors and just dose. just have to find the cheapest way of finding the 2 part.
Make it yourself. It is really easy to follow Randy Holmes-Farley's recipe. Cheap too!
http://reefkeeping.com/issues/2006-02/rhf/index.php

If you have a bit of money and want automation buy a litermeter and just set it to the right amount.
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Old 10-03-2006, 05:35 PM
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Originally Posted by solbby View Post
Unless I am wrong isn't it Calcium hydroxide? there is no carbonate portion to it or contained within it.
From what I've read, kalkwasser does provide alkalinity.
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Old 10-03-2006, 05:35 PM
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My chemistry is certainly weaker than yours but I think this excerpt from an article by Dr. Craig Bingman explains things:

Limewater
Limewater7 (also known by the German term kalkwasser) has been used very successfully by aquarists for a number of years, and it is the system that I use on my tank. It is comprised of an aqueous solution of calcium and hydroxide ions that can be made by dissolving either quicklime (calcium oxide, CaO) or lime (calcium hydroxide, Ca(OH)2). The only inherent difference between the two is that if you add a molecule of water to quicklime, you get lime, and that a great quantity of heat can be generated when that happens.
CaO + H2O à Ca(OH)2
Quicklime + Water à Lime
Consequently, dissolving quicklime can make water quite warm, especially if an excess of solids are added.
The calcium ions in the solution obviously supply calcium to the tank, and the hydroxide ions supply alkalinity. Hydroxide itself provides alkalinity (both by definition2 and as measured with an alkalinity test), but corals consume alkalinity as bicarbonate6, not hydroxide. Fortunately, when limewater is used in a reef tank, it quickly combines with atmospheric and in-tank CO2 and bicarbonate to form bicarbonate and carbonate:
OH- + CO2 à HCO3-

OH- + HCO3- à CO3-- + H2O

Once in the tank at an acceptable pH,8 there is no concern that the alkalinity provided by limewater is any different than any other carbonate alkalinity supplement. The hydroxide immediately disappears into the bicarbonate/carbonate system. In other words, the amount of hydroxide present in tank water is really only a function of pH (regardless of what has been added), and at any pH below 9, it is an insignificant factor in alkalinity tests (much less than 0.1 meq/L). Consequently, the fact that alkalinity is initially supplied as hydroxide in not to be viewed as problematic, except as it impacts pH (see below).


http://www.advancedaquarist.com/issues/feb2003/chem.htm
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Old 10-03-2006, 05:48 PM
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OK, my bad! Alkalinity is provided indirectly, I guess you would need alot of water flow to provide the nessesary CO2 to the system.

I wonder what the writer means by "it quickly combines with atmospheric and in-tank CO2 and bicarbonate to form bicarbonate and carbonate". Meaning wouldn't it combine with CO2 in-tank only. Additionally to think that the hydroxide ion will only form with CO2 is a mistake, I would think that it would react with a number of different molecules. If not enough CO2 is present then carbonate could be limiting.
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Old 10-03-2006, 05:53 PM
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Did I just catch you on a hard science question????? I can go to my grave happy now. LOL
I reponse to your questions, you have now moved beyond my ability to respond. Bingman's work is very good on the subject, and I believe Holmes-Farley too has written a fair ammount on the subject.

Cheers,

Randy
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Old 10-03-2006, 05:58 PM
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The "atmospheric" CO2 is probably the surface of the water. You're getting (a bit) of reacton at the water's surface. That's why kalk reactors are usually sealed containers.


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Old 10-03-2006, 06:00 PM
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Did I just catch you on a hard science question????? I can go to my grave happy now. LOL
I reponse to your questions, you have now moved beyond my ability to respond. Bingman's work is very good on the subject, and I believe Holmes-Farley too has written a fair ammount on the subject.

Cheers,

Randy
Yes you did! See that is what I get for taking Chemistry , makes me remember my loathing of Physical chemistry.

Anyway, getting back to nuts and bolts, I use to dose Kalk and I just never liked the pH spike. Additionally, my SPS also never grew or colored up that well either, but back then I didn't have much flow as now (tunze didn't exist yet) so possibily I wasn't getting enough CO2 into the system to provide the indirect carbonate.

What I do like is the two part is a direct addition of the nessesary ingredients for calcification and does not have any side effects (pH fluctuations) that I have found/seen yet.

Last edited by ShaunW; 10-03-2006 at 06:06 PM..
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Old 10-03-2006, 06:40 PM
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I conceder a calcium reactor as a alkalinity reactor with a side benefit of calcium, you still have to dose calcium chloride with sodium bicarbonate (pH value of 7.0) and sodium carbonate (to bring up the pH value of the sodium bicarbonate).

I find that a dry form of calcium and DKH buffering system more economical then the liquid form.

As for the Kalkwasser reactor, it’s great if you don’t mind spending that kind of money. A five gallon bucket with a ball valve attached is the way to go for the money.

I use Kalkwasser as a ph stabilizer, with a side benefit of calcium and you still have to dose calcium chloride with sodium bicarbonate (pH value of 7.0) and sodium carbonate (to bring up the pH value of the sodium bicarbonate).

gettanked
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Old 10-03-2006, 08:06 PM
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Originally Posted by gettanked View Post
I use Kalkwasser as a ph stabilizer, with a side benefit of calcium and you still have to dose calcium chloride with sodium bicarbonate (pH value of 7.0) and sodium carbonate (to bring up the pH value of the sodium bicarbonate).
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Old 10-03-2006, 08:30 PM
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Quote:
Originally Posted by solbby View Post
I wonder what the writer means by "it quickly combines with atmospheric and in-tank CO2 and bicarbonate to form bicarbonate and carbonate".
BC is correct.

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Originally Posted by bad coffee View Post
The "atmospheric" CO2 is probably the surface of the water. You're getting (a bit) of reacton at the water's surface. That's why kalk reactors are usually sealed containers.
B
OH- reacts with surface of the water which is exposed to atmospheric CO2 to form HCO3- and then quickly converted to solid Ca(HCO3)2 which is why kalk loses its potency when it is sitting around for too long and the white stuff you get at the surface of the solution.

Quote:
Originally Posted by solbby View Post
Meaning wouldn't it combine with CO2 in-tank only. Additionally to think that the hydroxide ion will only form with CO2 is a mistake, I would think that it would react with a number of different molecules. If not enough CO2 is present then carbonate could be limiting.
You are correct. There are other positive ions in the water that will compete for the OH which is a negative molecule. H+ is an example. H+HO=H2O and that will not contribute to the alk in the tank. CO2 is abundant in the tank b/c all the organisms produce CO2 except photosynthetic organisms (but only during the day they consume CO2, at night they produce CO2)
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