Kalkwasser timeline to calcium carbonate

[ScottR]

Kalkwasser is calcium hydroxide and is great when added to an ATO. Has really kept my alk stable. At about 6.6. I’m happy with this number. But when mixing a gallon of this, I’m worried that perhaps the kalkwasser will slowly turn to calcium carbonate in the presence of CO2. Are there any available guidelines for how long kalk can be kept before becoming useless? I guess the only way to truly tell - without testing the ATO water - is your Ca and alk will decline even though your ATO continues to add top off water.

 

[JCOLE]

Kalkwasser is calcium hydroxide and is great when added to an ATO. Has really kept my alk stable. At about 6.6. I’m happy with this number. But when mixing a gallon of this, I’m worried that perhaps the kalkwasser will slowly turn to calcium carbonate in the presence of CO2. Are there any available guidelines for how long kalk can be kept before becoming useless? I guess the only way to truly tell - without testing the ATO water - is your Ca and alk will decline even though your ATO continues to add top off water.

I use kalk also and love it. I am always changing buckets every 3 days so I cannot answer the longevity. I have always read about 2 months as long as it is sealed with no oxygen getting to it. I believe Randy said something about that.

 

[Gexx]

so long as you arent mixing it continuously a film will form over the top which will protect the rest of the bucket. My ATO is a 5 gallon bucket with a hole cut in the top just big enough to get the pump line/cords through. Mine lasts ~1-2 weeks depending on humidity and I havent noticed any changes over that time.

 

[SMSREEF]

Kalkwasser is calcium hydroxide and is great when added to an ATO. Has really kept my alk stable. At about 6.6. I’m happy with this number. But when mixing a gallon of this, I’m worried that perhaps the kalkwasser will slowly turn to calcium carbonate in the presence of CO2. Are there any available guidelines for how long kalk can be kept before becoming useless? I guess the only way to truly tell - without testing the ATO water - is your Ca and alk will decline even though your ATO continues to add top off water.

I use Kalk for my nano. I mix up a gallon and it lasts me about a week and a half. I use a doser at night so I add stable amounts every night. My alk and calcium don’t drop any more when the gallon is almost empty.

Although I do worry about what you describe and set up my gallon to try to limit the CO2 that can enter. I first put on press’n Seal, then screw on lid, then puncture through press seal with tubing that fits really tight.

 

[Randy Holmes-Farley Verified Community Expert]

Kalkwasser is calcium hydroxide and is great when added to an ATO. Has really kept my alk stable. At about 6.6. I’m happy with this number. But when mixing a gallon of this, I’m worried that perhaps the kalkwasser will slowly turn to calcium carbonate in the presence of CO2. Are there any available guidelines for how long kalk can be kept before becoming useless? I guess the only way to truly tell - without testing the ATO water - is your Ca and alk will decline even though your ATO continues to add top off water.

I showed that in an unstirred, closed Beute trash can, that is was stable for a month at least. I used it over 1-2 months. Closed and unstirred are both important.

 

[ScottR]

Thanks for all the input. I guess the consensus is, especially with Randy’s input, a month is nothing to worry about. I keep my sealed and not stirred. I guess stirring will mix the CO2 with the mixture and react with the CaOH2. Makes sense.

 

[CNDReef]

Usually I get a film on top of the water that acts like a barrier. I try not to break it

 

[Dal-Reef]

Usually I get a film on top of the water that acts like a barrier. I try not to break it

Just curious when you add more Kalk to your ATO how do keep from breaking the barrier?

 

[CNDReef]

If I’m adding more kalk it’ll break it but I’m adding more water as well and that’ll turn into a fully saturated solution. I don’t use it in a ato. I don’t believe it should be advised at all through a ato. Drip it or dose it into the tank. I don’t have space for another large container ( ato is 7 gallons) so I use a reactor right now. You could simply have a 5 gallon bucket of kalkwasser and setup a new one before you run out and swap them out. The trick is not to keep moving the top layer of water so there’s no gas exchange

 

[ScottR]

I use it in my ATO and have been for a couple of weeks now. I was taking alk readings daily (now less frequent) with a Hanna checker. Alk is always 6.6 - 6.7. I’m shocked with how steady it is. Ca fluctuates a bit more but stays around 450 but I’m also dosing Ca.

 

[SMSREEF]

I use it in my ATO and have been for a couple of weeks now. I was taking alk readings daily (now less frequent) with a Hanna checker. Alk is always 6.6 - 6.7. I’m shocked with how steady it is. Ca fluctuates a bit more but stays around 450 but I’m also dosing Ca.

What if it dumps a bunch of Kalk in due to sensor issue... what do you think about setting up a dosing pump with steady rate and use ATO for only RO water?

 

[ScottR]

What if it dumps a bunch of Kalk in due to sensor issue... what do you think about setting up a dosing pump with steady rate and use ATO for only RO water?

I do have this worry actually. I also have the worry of my ATO throwing off my salinity as well. Not saying it’s perfect or fail proof.