I'm not sure what my problem is, actually. I have had a gross brown/red coating on my sand on one side of my tank (the side that gets some sunlight), and a dark green on the other side (away from the sun) for many months. My water params are all good. No phosphate, nitrate. I use RO
water and always have. No snails will eat this stuff and nothing I do gets rid of it. In my depseration I am looking at chemical fixes.
Oh, and I've tried to siphon this stuff but it takes too much of my sand with it, and it just comes back.
29 gallon tank
40 lbs of LR
1.5 inches of LS
CPR BakPak skimmer w/ preskimmer
Aquaclear 201 and 301 powerheads
Tronic 100W heater
2 20W NO
Snail crew, Peppermint Shrimp, 2 Skunk Cleaner Shrimp, Percula Clown, Watchman Goby