Purple sand?

[Shap0311]

I seem to have an abundance of purple growth on my live sand. What causes this and how to fix it?

 

[Gregcoyote]

Looks like Cyanobacteria. Increase flow to these areas and be sure you aren't over feeding. This stuff can be siphoned out with the substrate, then clean the substrate and put it back into the tank. Stirring this stuff up without removing it is a waste of time as it will resettle.

I can't tell clearly from the picture, but if it is pink Coraline algae growing on the substrates, leave it alone.

 

[AquaRick]

+1 cyano

 

[Shap0311]

Thanks guys. I siphoned out the sand and did a PWC also. We will see how it does. Also cutting back on the feeding amount.