I have a fairly new 55 gal tank, and I need some advice on this algae that is growing all over my rocks. It ranges in color from light to dark green, and is very hard to remove. I'm running a 2xT5 Aquaticlife lights, 0930-1730, (yes, this tank size requires at least 4xT5). I recently added some Seachem Phosguard, and my phosphates are testing at zero with an API test kit. My nitrates are at 10 ppm, (again API). I'm running a Fluval 305 canister filter right now, (50g carbon, 125 mL phosguard, biomax, prefilter and polishing pads) so I understand that nitrates will be problematic. I've talked to a few people about it, and was told that this form of algae was 'good,' and would 'turn purple' after time. Wondering if the previous statements were true? If not, what can/ should I do about it?
