hi, i'm new to the site and have joined because i'm having a few tank problems and amhoping some members would have some sound advice.

The problem is that the tank is 7 months old and i just seem to keep losing fish. it is a marine tank i should have said.
In the last 3-4 weeks i have lost 11 fish from a coral beauty to clowns and a Yellow tang
The test i have done all show a clear tank and the local supplier tested the water and had the same result. i use ro water with reef crystals enriched blend.
any ideas or help would be really appreciated