Green powdery algae

[Bret61081]

ok...I am posting this for a friend. He has a 150 FO system that has been running for about a year and a half. The tank sat empty for about 5 months(filters running with autotopoff from RODI unit, just no lights) with no fish(after the hurricanes last year when they all died). About 2 mnoths ago he started getting back in to the hobby and he did a complete water change on it...added some fish and everything has been running great. He has a skimmer large enough to power a 300G tank and a wet/dry for the same. Recently he upgraded the lighting(formerly 2x400's and 4x96 but only used the 4 PCs) b/c he was planning on adding corals to the Orbits(I think) fixture with 3x150s and 4x96 and also added a refugium at the same time(using a 20GT drilled tank and a 2x24w 10k fixture for that filled with different macros, LR and Mircale mud) about a week and a half after adding the refugium and new lights his tank started to turn green. Its not the green coraline type its a real fine powery stuff. You can run the magfloat over the glass and within an hour its completely covered again! We tested everything we could think of...Phos are at .1(has a phosban reactor hooked up), Nitrates are around 10 and everything else was undetectable. He is going to have the LFS come do another water change this week even though they just did one 2 weeks ago! Anyone have any idea what this can be! I am going to have him send me a pic and I will try and upload it later this evening. Thanks for the help!

[Bret61081]

Think a UV will help? Anyone??

[ACBlinky]

Sounds like flim algae, pretty normal - this is one of the reasons some of us leave Mag-Floats in our tanks. Given light and nutrients it's going to keep appearing, but once things get balanced out, algae in the fuge start to grow and the tank matures it should ease up and you'll only have to clean the glass every few days or even less.