Calcium carbonate instead of calcium chloride?

sktn77a

Gold Supporter
May 16, 2010
1,951
Chapel Hill, NC
"Oh dear, the sky is falling" (says Eore) ;)

I accidentally ordered powdered calcium carbonate instead of calcium chloride to raise the hardness in my pool. Can I use the calcium carbonate or must I toss it in the trash (the seller doesn't take returns)?

Thanks,
 

JamesW

TFP Expert
Mar 2, 2011
21,568
Calcium carbonate would act like sodium carbonate and your ph and TA would go sky high.

If you need to raise your ph it might be useful. Otherwise, probably not.

I'm not even sure that it will dissolve easily enough to use.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,446
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
It won’t dissolve in water at normal pool pH. You would first have to convert it to a chloride by mixing it with an acid but that would be dangerous to do in an uncontrolled reaction with such large quantities involved.

So yeah, toss it....or mix it into your garden soil as an amendment (if your soil pH is too low).