ok,let me explain my tank,its a 60 cube,90lbs live rock,75lbs live sand,been running for 3 months,closed loop (lil giant 3) with lil ginat 2 return,asm g-2 skimmer,400 watt halide,4- 75 watt vho's.1/4hp chiller,tank stays 76%.water checks out perfect,PH is 8.2-8.4.tank was doing great,but now all of a sudden my corals dont open fully.i was using reef crystals salt,but over last few bi-weekly water changes ive switched to new seachem reef salt.any ideas?