fish keep dieing!!

[barna]

hi all, i have a 90 gallon reef tank with all kinds of corals that are for the most part doing pretty well. i have an excess of browninsh algae on lots of the live rock and i have purchased meny snails and crabs to get rid of it but they never last long enough to clean the tank. also any fish that i buy never seem to lastmore than a few months.

its a 90 gallon and all the nitrate, amonia, calcium..ect ect levels seem to be in check. i use RO water and more recently i have been doing my weekly 10% water changes

does anyone have any ideas? also the tank is located in a hair salon, so i was thinking maybe some sprays and what not could be contaminating the water? maybe i should be adding carbon to the sump?

 

[BIGgourami]

Running carbon wouldn't be a bad thing at this point

Do the fish display any symptoms of illness

 

[Myteemouse]

what salt are you using
What lights, filtration??

 

[Googz]

Could just be where you are buying from. Bought two fish from this one store both died and then some time later down the road i bought another one from there and it died as well. During this time I had other fish that were doing fine and showed no signs of illness + params were all good. What type have died?