Mystery Algae

[Alaska_Phil]

My tank has had this brown/green slime algae for over a year now. I just swapped out the tank (old one was actually a reptile tank and the bottom was sagging ominously) and the problem come along with it. This doesn't look like cyano, it grows in tough sheets that can't be blasted off with a turkey baster. Sometimes the sheets can be peeled off the rocks though. And it gets covered with bubbles during the day. Below are the tank details and a photo of an alage covered rock. This is really ugly stuff, and I'd really like to get rid of it permanently. :(

50 gal Long (48x13x19)
CPR Backpack 2 skimmer
110W 10,000k PC lighting
32W NO Actinic light

SG = 1.024
CA = 400
dKH = 120ppm
Nitrate = 0
Phosphate = 0.5

http://reefcentral.com/gallery/showphoto.php?photo=197203

Thanks
Phil