I am having alot of trouble keeping anything alive in my saltwater tank. My setup is as follows: 55 gallon tank with crushed coral substrate, approx 25lbs of cured live rock, an aquaclear 70 hang on back filter with just mechanical filter in it, and a powerhead aimed at live rock for more movement and bio filtration. I have a marine light which is on about 9 hours a day. Through my whole issue my water parameters have been: PH 7.8, Ammonia 0 nitrites 0 and nitrates 10ppm or less, salinity 1.024 and temperature is 78 deg.

I know i need to eventually get a protein skimmer however i have not had more than two fish both under an inch in length in my tank at the same time so there isnt really to much of a bio load (live rock is probably biggest load)

My first two fish were both ociallaris clowns and one only survived 2 days and the other started showing signs of excessive slim and was going white, eventually died after 5 days. I researched this and determined it may be brooklynella disease. So i left the tank fishless for 4 weeks after this to allow parasite to die. After 4 weeks i put a bangaii cardinal in and he seemed to be doing ok for a week so i placed another bangaii cardinal in and within 3 days both were dead. I started getting sick of wasting money so my newest addition has been a little cheap damsel fish and two hermit crabs. they have been in the tank for 3 days and now the damsel is at the bottom not looking to good.

I have talked to lfs and they do not know what the problem is.

The only other note is that the damsel seemed to be breathing heavy the whole time, i was wondering if it was getting enough o2. I do not have an airstone but i have lots of surface turbulance with my filter and powerhead.

Please help!!!