Hey my first post.

so heres my problem. I have these odd white things in my tank. I tried to rub them off with everything from a scrubber to a razor, nothing worked. I have some pictures here and was wondering if anyone can tell me what they are, and if they are bad. Also they do not move AT ALL and also seem to only form on my internal overflow. Here's some pictures.

0509082155-01.jpg - Image - Photobucket - Video and Image Hosting

0509082155-01.jpg - Image - Photobucket - Video and Image Hosting

Heres some info on my tank setup. As far as I know the only water quality problem I have is high nitrates (around 80 ppm). the only thing alive in there is some live rock (about 60-65 lbs) and a chocolate chip starfish.

72 gallon bow front.
marineland tidepool
protein skimmer
uv
automatic topoff system
t5 atinic lights