Carbocalcium, pH, and Kalk head spinning

[USMA36]

I am running a 200 gallon total water volume SPS dominant reef tank. I’m dosing 100 of carbocalcium. My tank is in my basement tightly sealed house 7 months out of the year. With that I’m always battling low pH. I run a co2 scrubber recirculating through my skimmer cup. It’s not enough to keep pH above 8. I have started dosing Kalk I’d like to dose it at night to help with the ph swing. Are there any potential problems doing it this way? Should I only dose the carbocalcium during the day? My second question is how does calcium formate effect ph? If my alk is on the lower end around 7 will it be harder to maintain a higher pH conversely will running a dkh of 8.5 or 9 will my pH be higher or does the calcium formate method of dosing not play any part in the pH level? I am overthinking this and it’s making my head spin. Thanks in advance.

 

[Miami Reef]

I am running a 200 gallon total water volume SPS dominant reef tank. I’m dosing 100 of carbocalcium. My tank is in my basement tightly sealed house 7 months out of the year. With that I’m always battling low pH. I run a co2 scrubber recirculating through my skimmer cup. It’s not enough to keep pH above 8. I have started dosing Kalk I’d like to dose it at night to help with the ph swing. Are there any potential problems doing it this way? Should I only dose the carbocalcium during the day? My second question is how does calcium formate effect ph? If my alk is on the lower end around 7 will it be harder to maintain a higher pH conversely will running a dkh of 8.5 or 9 will my pH be higher or does the calcium formate method of dosing not play any part in the pH level? I am overthinking this and it’s making my head spin. Thanks in advance.

I believe that calcium formate has a very slight ph lowering effect.

Personally I’d use a 2 part containing sodium hydroxide for part 1 and calcium chloride for part 2. That will have the same ph boosting effect as kalkwasser, but it will fully support an SPS system while kalkwasser won’t be able to supply the entire demand. (I’d personally use that 2 part system and not use formats nor kalkwasser as it’s not needed IMO).

Kalkwasser and sodium hydroxide have the same ph effect per unit of alkalinity added.

Here’s the thread of the recipe by Randy: https://www.reef2reef.com/threads/second-new-diy-two-part-recipe-with-higher-ph-boost.357080/

Beware, sodium hydroxide is very caustic. Do not get on skin or eyes. Research before handling.

 

[sneekapeek]

Sodium hydroxide and calcium hydroxide have similar potency, the only nice part is you can tweak calcium separately, but specific gravity may raise!

 

[Randy Holmes-Farley Verified Community Expert]

Formate is similar to bicarbonate in having a very slight pH lowering effect, which you wont detect unless you look very carefully,

I’m not a fan of recirculating skimmer scrubbers because you lose potential oxygenation from fresh air, but many people use it.