I have had problems since I set this tank up with low alk and Ca. OK, so here is what I have used to try and compensate... dKH builder, kalkwasser, Kent liquid calcium, Turbo calcium, ESV Bi-onic, Magnesium, Ocean's Blend 2 part (similar to ESV) According to my test kits, (Salifert everything, except CA is seachem) My alk this week is at 12 dKH (after adding builder for 2 days) and Calcium is 300. I cannot get my hands on a mag test so I take a sample to the LFS to check that for me. They use LaMotte. So, with that kit you need to find the Total Hardness and subtract the CA hardness to get the Mag hardness. Here is the problem....The test kit for total hardness (rec. value is 200-400) was over 1000 when we stopped the test, and the CA said it was over 600. Now, is this possible? I could not determine a mag number because we could not get a result from the other tests. Also, I don't understand how a recommended total hardness is 200-400 ppm when Mag alone should be 1300 ppm, and Ca should be 450 ppm....that alone is 1750 ppm. Am I totally confused or what????