Help

[Richard_Dicosimo]

Hey have been reading posts here for a while lotsa good info going around. i have a 90gal reef tank that has been running for 3 months. i have an aquamedic skimmer on it rated to a 250 gal tank. a 400 watt mh and a atintic not sure what rating i have 1 rena xp3 canister filter with phos gard in it and sum water scrubers. i have 2 power head 802's. i keep my temp at 80 deg my atintic light runs for 10 hours my mh runs for 8. my last water test results came up, Calcium 500mq/L Nitrate 20ppm Phosphate 0.5ppm Amonia 0ppm nitritre0ppm ph8.2 kh/alkalinity 12.2dkh


OK MY PROBLEM

i have no problem keeping corals in fact they grow at a suprising rate(suprising to me at least). but my fish started dying about 2 and a half weeks ago and now all that i have left are my 2 sleeper gobys. i had 1 percula clown 3 yellowtail damsles 1 lawnmower goby and 1 blue tang all die on me. now im not a super experience reefer but i am a competant person. i have read several saltwater books on setup and maintanace so other then maybe adding the fish a little to fast i am not sure what im doing wrong, and im kinda afraid to buy anymore fish. what i dont understand is i thought corals where harder to keep then fish and all mine are doing fine the only coral i have had die on me is one that i ordered from vancouver and it didnt make the trip. PLEASE HELP ME