[cbeatty]

I'm having a real issue with this rusty stuff growing on my sand. I don't think its red slime due to color and it doesn't sheet like red slime usually does, more like a fine copper colored algae growing on the sand. Strange thing is that it grows only on my sand and nowhere else. Nitrates and Phosphates aren't zero, but decent. It's a 10 gallon nano with a good amount of live rock (roughly 17 lbs.), a decently functioning nano skimmer and a dual head penguin for flow and rough mechanical (no carbon). I do 50% water changes every 2-3 weeks and it still keeps coming back. Also, always use RODI water for changes and top off (daily). Got an 80w CF fixture for Xmas which seems to have made it owrse. Just dropped in some caulerpa in from a buddy of mine to help reduce nutrient load and the stuff is now growing on it as well. Only one small oscellaris clown currently who I meagerly feed to encourage foraging and reduce nutrient load. Three power heads in place which create high flow over the sand and ironically it doesn't grow where the flow is very slow on the sides/back bottom of the tank.

My practice has been to pull it in big sheets off the tank (along with the sand its stuck to) every time I do a water change and clean the tank. Again, the red slime (or possibly diatom) is growing only on the sand and the caulerpa. Had a green hair algae problem on the sand previously, now switching to this muck. Hermits and snails really don't touch the stuff but keep the live rock super clean. Any ideas as to how to get rid of it? Is one clown too many for a 10 gal tank? Any and all inputs appreciated.

[glampka]

Check your silicates - diatoms feed on them.

[cbeatty]

How would silicates be high? I will go out and buy a test kit. Thanks,

[Taras1]

It depends on how effective your RO?DI unit is. You can check it by testing for Residual Dissolved Solids. Also, it can be from overfeeding and excess phosphates. "Sheets" of the stuff usually mean there's something else going on.

[Jay03GT]

if it comes up in sheets it sounds like cyano. I had some that was similar when the tank was still finishing cycling. Suck it out with a siphon, and try to do smaller, more frequent water changes. The caulerpa will help, but probably take some time to get there.