Black/Purple Gel on Rocks

[rcmcg]

My FO tank has been up and running since the first of the year. The rocks have started getting some of the purple that I see in the tanks at the LFS. I am assuming that is a good sign. It kept getting darker, even looking black. All the water perameters are normal. During a water change last night, I took out one of the rocks and there is a black/purple gel covering different areas. What is this and what do I need to do? Thanks for your help!

 

[drew2005]

Sounds like cyanobacteria(red slime algae). Cut back on your lighting and feeding. You may need more flow to those dead areas. Check this link out https://forums.saltwaterfish.com/t/73002/how-to-rid-your-tank-of-red-slime2

 

[rcmcg]

Thanks Drew! That is a great post, I am going to print it out and give it a try. It is just in patches on the rock, so maybe it won't be to tough to get rid of.