I did a water change last night and before I put the new water I tested the salinity level, as a always do, but this time I wanted to test for the calcium. I have been hard for my to maintain my CA at around 400 even with heavy doses of CA supplements. I couldn't believe that the newly made water at SG of 1.025 had the CA level at just below 300!!!!! I use the Pinpoint CA monitor so I believe it's pretty accurate. Is it possible that I have a bad batch of RC?



