What is this????

[Luke809]

Need some help can anyone ID this? It's not slimey I change about 30% water twice a week. All my parameters are where they should be. I have a uv steriliser running on the tank as well.

Any help is appreciated

Thanks in advance

 

[Uberhoust]

Is the growth confined to the rock or is it elsewhere in the tank as well. If it is confined to the rock do you know what kind of rock it is?

 

[mbsqw1d]

Is it a plastic hardscape? Could be where the coating has worn away and the plastic its made from is red. If it isn't plastic, then yeh it could be the start of some cyanobacteria, usually the result of high phosphate/low nitrate or high nitrate/low phosphate