We are fairly new to the saltwater hobby. We have a 35 Gal tank with a bio wheel filtration system. We have 2 Clarks Clownfish, a blue damsel, Koran Angelfish, Mandarin Goby, and a Lionfish. We also have cleaner snails, crabs, ornamental shrimp, and about 30 lbs of live rock. I had 2 anemones- they died and almost ruined my tank. I want to add some coral or more anemones but I am terrified bc I dont want more problems with the tank. I dont know if I need a sump and power heads...Can someone please give me some advice about where to begin?