calcium high, but I don't dose calcium

[Randy Holmes-Farley]

OK, it's just pretty low for whatever reason. You can use baking soda to boost it, if your target alkalinity is higher (I recommend 125-200 ppm calcium carbonate equivalents or 2.5-4 meq/L).

 

[mhsmith]

What about using the washing soda if the ph is low? I think I read that in one of your articles.

 

[Randy Holmes-Farley]

Yes, washing soda is also fine.