I have 2 29 gal. tanks. There is 45 lbs live rock in each with 20 lbs live sand. (1" deep) I have 2 powerheads (170 gph each) in both tanks, a Visi-Jet Protein Skimmer, and a aqua-tech 20-40 filter. I am not sure what kind of lights but they are on 12 hour timers. The temp. in both tanks is 78 F. Sal. is 1.025. 0 ammonia,nitrite, and nitrate. PH is 8.4. I have a small snowflake eel, 6 blue leg crabs, and 5 nassarius snails in one tank. The other tank has 2 green damsels, 1 4-striped damsel, 1 ocellaris clown, 8 blue leg crabs and 9 nassarius snails. I have had the tanks running for about 2 months and I have had 1 ocellaris clown and 1 4-striped damsel die both within 2 days of purchase. I dont know what is killing them. The other fish are doing great. Any suggestions?