# How do you mix your calcium hydroxide?



## TankCla (Dec 31, 2010)

I am curious how are you mixing kalkwasser. 

I am dosing with ATO but I am mixing in a 1 gallon jug, then siphon 80% of the top water in ATO bucket.

The recipe is 2 teaspoons of kalkwasser for each gallon. I am mixing 10 teaspoons in 1 gallon, siphon into ato bucket and complete with ro/di water until full. It is easy this way for me. One gallon jug to clean. I can easily siphon water down to the white sediment. Don't have to raise ato pump 3" from the bottom of the bucket.

Now, my concern is the saturated solution. Can I put more calcium hydroxide in 1 gallon of water, or I have to stick to the 2teasp for 1 gall and mix it in a bucket.

How much calcium hydroxide that can be dissolved in 1 gallon of ro/di water? How much time do you need for the entire solution to settle down? 

How clear is the solution after you mixed it? Mine becomes lightly foggy over night.


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## lloydj (Apr 10, 2009)

3 teaspoons kalk, 45ml vinegar and 1 gallon RODI. shake well.


Not recommended to put more than 2 tablespoons in 1 gal RODI it wont dissolve.


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## TankCla (Dec 31, 2010)

You are boosting it with vinegar? Why?


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## lloydj (Apr 10, 2009)

It's basically allowing the kalk to more effectively buffer the water by donating the CO2 component to the OH of CaOH (kalk) forming bicarbonate (HCO3), Ca ion and CH3 (methyl group). This equates to a higher relative pH (potentially) and more calcium being able to stay soluble (by reducing calcium's chances of combining with straight-up carbonate (CO3) and precipitating), which happens when CO2 is short in supply.

It also liberates a methyl group (CH3) which can be used by bacteria as a food source. But if you really think about how much carbon you're adding with food alone, the amount of CH3 with this is pretty minimal - especially considering that most vinegar is 95% or more H2O. I wouldn't worry in the least. Not to mention you're probably dripping, not "pouring".


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## TankCla (Dec 31, 2010)

lloydj said:


> It's basically allowing the kalk to more effectively buffer the water by donating the CO2 component to the OH of CaOH (kalk) forming bicarbonate (HCO3), Ca ion and CH3 (methyl group). This equates to a higher relative pH (potentially) and more calcium being able to stay soluble (by reducing calcium's chances of combining with straight-up carbonate (CO3) and precipitating), which happens when CO2 is short in supply.


Interesting. This means, the solution will be more clear, right?



lloydj said:


> Not to mention you're probably dripping, not "pouring".


I am somewhere in between. I am looking on my pH readings, and every hour my ato turns on and pH is not going up much (between 0.1 ~ 0.3 with every dose)
I was worried, since I am not dripping, but pH range is between 8.0 ~ 8.2. More stable than before using kalk.


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## lloydj (Apr 10, 2009)

Correct, in my experience it dissolves better.

As long as your perimeters are in check, dont worry so much about your PH. IMO


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## UrbnRzqr (May 31, 2013)

I'm thinking of just mixing in my top off tank which is a 16 gallon tall tank. Reason being it has been a bit of a pain premixing this solution and doing so in a covered container large enough to do 16 gal. My brute bucket is big enough but I don't have a lid for it to prevent CO exposure.

There's also a layer of skim created when the kalk is mixed which would also help prevent exposure in the ATO tank. My thoughts were to mix in ATO tank but prior to doing so over topping off the main tank to provide a delay in ATO sensor triggering. Thus allowing the solution to dissolve and preventing the powder from going through.

So I guess I'd have to prop up the pump a couple inches and was also considering placing a small powerhead in the tank to help mix up the kalk. Downfall would probably be the increased intervals in ato tank clean up including pump and float.

This is something I'm considering doing by the way.


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## lloydj (Apr 10, 2009)

How is the dosing going? Seen any results?


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## TankCla (Dec 31, 2010)

Live stock is growing. Corals are looking better than ever. But my Ca readings are low, 380-400 with alk between 9-11 dkH. I am dosing 5 gallons of kalkwasser+vinegar in 5-6 days. Seachem Kalkwasser.

Any ideas why Ca is low?


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## altcharacter (Jan 10, 2011)

I've read that Kalk isn't the solution to getting higher Ca but rather maintaining Ca and Dkh. You need to raise your Ca up to the level you wanted it at with a 2 part like the B-Ionic then you can use Kalk to maintain it. 

I've been dosing with the 2 part up until now and I've just mixed my first batch of Kalk with 3 gallons of water for my ATO. I'll let you know how it goes


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## TankCla (Dec 31, 2010)

Last week, Friday, after the water change I had 440 Ca. Today 400, with kalkwasser.



Seachem Kalkwasser said:


> Reef Kalkwasser™is a pure calcium hydroxide with unsurpassed purity and solubility characteristics. Calcium hydroxide is used to prepare limewater (kalkwasser) solutions that will maintain calcium concentrations at natural seawater levels. Kalkwasser solutions maintain calcium directly and carbonate alkalinity indirectly. However, its capacity to perform these functions is dependent on evaporation rate and CO2 concentration. If these two factors are insufficient you can provide additional calcium with Reef Advantage Calcium™, Reef Complete®, or Reef Calcium™, and carbonate alkalinity with Reef Builder™ or Reef Carbonate™ (do not mix these directly with a kalkwasser solution).


For CO2 I add vinegar and it is not even maintaining. I probably should dose some Ca. I see a blooming in SPS growth. All of them have white tips and great PE. Maybe they are taking more Ca than I can imagine.


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## wtac (Mar 17, 2006)

I just want to clarify the chemical process in the kalk and vinegar method. Llyodj is correct in the overall but may have misinterpreted the stepwise process and molecular species involved.

Calcium hydroxide disassociates in water with the following chemical equation:

[1] Ca(OH)2 -> Ca (+2) + 2OH-

The reason why one adds so little to RO/DI water is that it has a low solubility at a higher pH, which itself creates. To get more Ca ions or dissolve more Ca(OH)2

Adding vinegar (acetic acid) to the solution helps in "forcing" more Ca(OH)2 into solution by dropping the pH. Vinegar in itself is a weak acid and does not completely "ionize" and "goes back and forth" from a non-ionized state to an ionized state because of the nature of the carboxyl group COOH:

[2] CH3COOH (acetic acid) <-> H(+) + CH3COO- (acetate)

The higher the pH of the solution, the more that the reaction goes in the right direction, and visa versa: to the left in acidic solutions

Combining the right hand equation 1 and 2 (qty is doubled to make a balanced reaction equation) you get the following reaction:

Ca(+2) + 2OH- + 2H(+) + 2CH3COO- -> Ca(+2) + 2CH3COO- + 2H20

The carboxyl group does not "break away" from the methyl group.

Ca precipitation is from dosing kalk water into the system: If too fast/not enough CO2 in the water, the hydroxyl group (OH-) will react w/the bicarbonate (HCO3-) to create carbonate (CO3-2) which will precipitate out w/calcium ions in the form of calcium carbonate.

Adding vinegar to the kalk mix:
-Dissolve more Ca(OH)2 for free calcium ions vs only using RO/Di water
-Not adding more chloride to the system associated w/dosing CaCl2
-Acetate (CH3COO) as a carbon source 
-Lose the aspect of buffer addition (OH-) compared to just using kalk *if* enough vinegar is added to make a neutral solution.

HTH


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## TankCla (Dec 31, 2010)

Perfect, then why do my Ca goes down with kalk+vinegar dosing? Not enough vinegar?


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## wtac (Mar 17, 2006)

I'm not caught up with everyones' systems and what they are doing but what was your Ca supplemental method prior to the kalk?

Saturated Kalk [email protected]/l and you will get more when dissolved w/an acid. How much more depends on how much acid is added. I'll have to do the math to get the Ca concentration based on the various recipes out there.

A drop in Ca, assuming that you have been dosing the same volume of kalk solution and kalk solution w/vinegar, I can only assume that the organic carbon source is fuelling the coral growth, thus increasing Ca demands and seeing lower Ca in system water.

Also Ca precipitaion will play a factor and kalkwasser is a funny beast to play with, IME


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## TankCla (Dec 31, 2010)

I am just thinking. What if I dissolve kalkwasser in sparkling water (H2O + CO2)? 
1 or 2 liters for a 5 gallons bucket of ro/di.


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## wtac (Mar 17, 2006)

Not really practical as the CO2 will fizz out too fast to be of benefit. Vinegar is significantly better/easier/stable manner of dropping the pH to get more Ca from kalk.


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