I HAVE A 55 GAL FOWLER TANK WITH LIVE SAND AND ABOUT 40 POUNDS OF LIVE ROCK. I CAN KEEP ABOUT 3 FISH OK BUT IF I ADD MORE THEY TEND TO LIVE A COUPLE WEEKS AND DIE WITH NO SIGNS. THE FISH I HAVE ARE 2 CLOWNS AND ONE SHRIMP GOBY. IVE TRIED TO ADD DWARF ANGLES AND VARIOUS SMALL FISH. MY TANK PARAMATERS SEEM TO BE GOOD AS FAR AS AMONIA RUNS AT 0 NITRATES 15 PH 8.4 AND ABOUT 1.022 ON REF. WHEN I DO WATER CHANGES I USE PREMIXED RO WATER FROM THE AQUARIUM STORE. WHAT AM I DOING WRONG AND CAN ANY ONE TELL ME ANYTHING ELSE I CAN DO OR CHECK? I ALSO HAVE A HANG ON THE BACK FILTER ALONG WITH A HANG ON THE BACK SKIMMER AND A MAXIJET 1200 TO KEEP THE TOP OF THE WATER BROKE FOR GAS EXCHANGE. HELP PLEASE