Brown stuff (algae?) on my sand and rock

Hi,

I'm running a 240L (65Gallon) tank with 90L sump. Lighting cycle approx 9 hours per day. Aqua One skimmer, Phosban phosphate reactor, UV steriliser. Lights (2xBlue T8, 2xWhite T5) replaced 1 month ago.

Sump has cheatomorph and caulerpa (mainly Chaeto) growing well.

Parameters are good - NO2 @ zero, NO3 @ zero, Ammonia zero, pH 8.3, trace phosphates only. Only using RO water (no tap water). Water changes every 2 weeks.

Over the past couple of months, I've had brown stuff appear on my sand and increasingly on my live rock. I'm able to shift it pretty easily with a turkey baster but it is growing and taking over more of the sand and rock surfaces.

Any idea what's causing this and how I can get rid of it?

Thanks

 

Sounds like cynobacteria. Do you have a picture to confirm?

 

picture would help, sounds like the tank is old enough to have already survived the initial cycling outbreaks, another possibility is flatworms perhaps. I had an outbreak in my tank and it started like that, looked like little brown algae spots till they start multiplying and get a little bigger, then they will form a mat and start covering the rocks.

 

Thanks for your replies.

I've added a few pics - they're a bit blurred but hopefully good enough to show the problem. If not, I'll post some more.

I'm not sure but I don't think this is cyano - not smooth/slimy. Open to ides and advice though.

Thanks

 

It's some kind of photosynthetic organism. Algae, cyano....

 

Thanks - any idea how to get rid of it?