Well, I'm guessing this isn't good news because earlier you had mentioned that if my tap was 200PPM or less then I could get away with using the CalMag but I just measured my tap and its at like 305PPM and using the brita filter doesn't seem to really make a difference either. My 40gal. resv. that I have my clones in right now is at 965PPM, with only PH balanced brita filtered water and Ionic Grow nute solution.