I CAN'T GET RID OF THESE DIATOMS! My tank has been up and running for about 4 months now, and the problem still exists! I did a 72 hr period of lights off, and it put a dent in it, but won't completely knock it out. I water change 30% once a week in my 50 gallon FOWLR tank, and yesterday I tried to skim all the algae off the sand with a vac. I wake up this morning and it's back!!!! It's recently covered almost all of my rocks, and I blow if off with a turkey baster, but it's still driving me crazy! My tank is looking WAY to brown! I did water tests, and I do have ONLY phosphates, minuscule amounts. Do you think it could be a circulation issue? I have a powerhead circulating 800gph. Do I need another one? Also, ATM, I am in the process of building a sump, so I have a canister filter, eheim 2213. What's the protocol on cleaning the media? I don't have a large bio-load ( 1 wrasse, 1 blenny), so should I have already cleaned the media??
Any and all help would be greatly appreciated!
Any and all help would be greatly appreciated!

