This is my first time posting here so be gentle. I have a 125gal reef tank that is 2yrs old. A few months ago, I started seeing this algae or something start growing in my tank that I'll try to describe. It's rust colored, grows in flakes. It's not slimy or stringy, it will blow around if you blast it. It covers the sand bed and live rock, doesn't bother the corals. You can siphon some of it out but it's not easy. My tank parameters are within normal ranges. I have metal halides for lighting. I run GFO to keep phosphate as close to zero as I can. No carbon dosing. Use two-part for Ca and Alk. Anyone ever see this before, what is it? How do you get rid of it? Thanks for looking.
