o.k i set up a saltwater tank with crushed coral as substrate and liverock.everything was fine.i added a 6 line.2 clowns,atl.blue tang etc.they were all fine eating and everything.a few days later they started acting a little weird like getting this white film on them and stuff.they all died...............except starfish,shrimp,crabs,snails.now i went to my lfs and they told me i need a heater because they need a set water temperature.i bought one along with a damsel fish.that was monday.today i come home to a dead damsel.i also had treated the tank with mystess or something like that from microbe-lift incase it was a fungus or something.all my water is fine.i have high p.h.almost zero nitra,nitri,and ammonia.my salt was a tad bit high but nothing crazy.what can it be please help................give me a clue.if not its going to be taken apart and im going to stick to what i know....fresh water