New Member Needs Help! (Long)

[Carrie C]

We have a 65 gal saltwater tank, which consists of the following:
Equipment:
Eheim Canister Filteration system
Red Sea Protein Skimmer
2 402 Powerheads
1 900 Powerhead
1 1200 Powerhead
Our temp is kept at a consistant 78F and test our water weekly.
A few months ago our eheim started flooding the floor, so we talked to someone who works at a fish store, who told us that our live rock (we've got over a hundred pounds) would do what the eheim did, only better. We were also told to load our tank with invertebraes (we've got 25 hermit crabs, 2 emerald crabs, several anenome crabs, 30 or so snails, a konk and 2 sea cucumbers) we wouldn't need to have the eheim. So we did. We were also told to do mass feedings 2X a week, and that's all. So we did. It seemed to work for a while.Earlier this week we found out that we were given bad advice. We had the ehiem fixed and put it back in. We are feeding them flake food, brine shrimp and lettuce on a more regular basis now because they are malnurished. We noticed that some of our fish had a bit of ick, and their fins looked frayed, and bitten. We put "Kick-Ick" in on thursday night but it's not doing anything. In the past 3 days, we've lost a yellow eyed tang, flame angel, mandarin goby and today a orange clown. Our other Orange clown swims stationary on the sand, the yellow tang and coral beauty wants cleaned constantly, and they all dart around the tank, as if itchy, or irritated. We also have a long nose and flame hawkfish, a maroon clown fish, blue and yellow damsel, and a fire goby. We're really upset, we love our tank and need help desperately! Should we wait out the "Kick-Ich" or try something else? I don't think their dying of ick because it's just slight, before we find them dead. We also have many corals which are fine.