I'am confused? I have a 75-gallon tank with 120 lbs live rock (7 years old) 100 lbs live aragonite; 350 watts compact with ½ 100k and ½ actinic light. My tank has been set up 2 months now. Ammonia = 0-.25, PH = 8.2-8.4, Nitrite = 0, Nitrate = 10-20. I have 2 Damsels, 1 Yellow Tang, 1 Kole...