The tank is 3 yrs old,never had any problems like this, salinity is kept at 1.024, ph at 8.2 to 8.3, temp 80 degrees, trates and trites at 0, amonia at o, Phos. at 0.1 calcium about 440. I do a weekly 5 gal water change, protein skimmer, wet/dry filtration, no carbon, 175 lbs live rock 125 lbs...