I have a 50-gallon saltwater tank. 90% live rocks and white live sand. Set up 2 month ago. I was off to a good start until now. I’ve had 2 clownfish, 1 yellow tang, three damselfish two was blue and one was black/white stripe, and one pork fish and 1 seahorse…. Plus 2 snails, 2 hermit crabs…. Its was doing fine but started with porkfish had ick on his body, I started treat the whole tank with ick medicine food from a fish store. The porkfish was getting better… however, the yellow tan died two weeks ago. Then porkfish getting its ick back again I treat with medicine food again a few times. Two of my clownfish dead in 3 days…then porkfish getting its ick again, I used SUPER ICK CURE only once a few days ago however it turned my full tank in blue…… since then I collected dead fish everyday … begin with damsel, then porkfish, only one seahorses left but he is not doing well either … I tested water, besides nitrate leave a bit high at about 40… all others all fine … I am so frustrated what’s going wrong ? All I can think its ick treatment killed all…. Any idea / help will be greatly appreciate!!!