Brown Sludge growing

[jap1]

I have this gross looking brownish-maroonish slime that's been growing for a while now on my sand. It started out as one little tiny spot. I've been removing it by hand every so often but it always comes back. Now it's on about half my sand. It's even getting on my rocks. I do weekly water changes ONLY with RO/DI. I have no fish in the tank yet. I've also been using PhosGuard. Nothing new in the tank for a couple of months. What is this stuff? What causes it? And how can I take care of the problem. This stuff is disgusting. Any help would be much appreciated.

[hobogato]

sounds like cyano or diatoms. try syphoning it out when you do water changes. how long has the tank been running?

[GaryP]

New tank = cyanobacteria & diatoms. This sounds like cyano.

Siphon like hobgato said. Also increasing flow in the tank will probably help, especially in the lower areas of the tank. Running carbon is also helpful.

[jap1]

The tank has been going since November. The slimes in the part of the tank with the lowest flow. I will add some carbon. I've never ran carbon before.

[GaryP]

Cyano likes dissolved organics (DOC) in the water and low oxygen levels. Filtering with activated carbon will reduce the DOC. Increasing the low will get more oxygenated water to the stagnant areas the cyano likes.

[discuspro]

What kind of salt are you using? Got a skimmer?

[jap1]

Cool, thanks Gary. I should get some sort of nano powerhead, huh?

[GaryP]

No problem, that's why we are here. A microjet or one of the smaller maxijets would be good.