Ok, I've taken my water to three different stores and all report low calcium numbers ranging from 125 to 150. However, the home kit I'm using registers are about 250. I'm using the Blue Devil DPD test kit. My DPD test seems to be about 70 to 100 points higher than the pools stores. Consistently.
This has been a big issue for me because I have some sort of crystallization deposits on the sides of my pool. The pool store kept telling me my calcium was 300-400 but my home test said 500-600. So I'd like to avoid having high calcium, but I'm not totally sure if I should trust my home test or not (seems pretty easy...add drops and multiply by 50).
Interestingly, my Jandy Aquapure salt chlorine generator manual suggests a calcium range of 150 to 400 so maybe I ought to stay pat regardless.