You said the tank was set up for a few years before you transferred it, did you let the tank cycle again after the transfer? Also, what are your phosphate levels? Without phosphate, all your algae will do is for off. Another issue is probably your feeding. I have a 200 gallon system and I feed 18 fish about 3 frozen cubes. Anything not eaten in a system will cause your skimmer to go crazy, esp frozen bc of the crude and and percentage of protein. Also are you using ro/di for your water changes and too offs? Not will throw everything and your system may actually be doing its job which is causing your nitrates to go crazy. Just trying to think out the box...