I have a 30 gallon tank, received established from friend. I added 30 lbs of new rock 3-4 weeks ago. Parameters are SP-1.0245, amm-.25, nitrite-0, and nitrate-80. Temp-78. right now I have a watchman goby, mandarin, 4 hermit crabs, a sand sifting star, and a blue damsell damsall. I just lost my coral angelfish this morning. I have a venturi type skimmer and a compact filter. I am new to this and have read allot but cant figure out what I am doing wrong this is the third fish that has died on me. He had swollen glossy eyes and had white powder like spots all over his body. I only had him a week, so he could of arrived ill! Any advice would be greatly appreciated from more experienced fish owners. thanks