So, my tank has been up and running about 6mths. It is a 75 gallon with 20G sump. Have so/so T5 lights on it right now, but just ordered 2- hydra 52s. My water parameters have been pretty stable. Ph 8.1-8.2, Alk 11, SG 1.025, Nitrate 5-10, phos 0-0.02. the only issue I have had is with Calcium...