Bright purple spots?

[Iceman72]

Anyone know what these bright purple circles are in my sand?

 

[bribo12]

Cyanobacteria a pest algae kinda. Could be low flow areas, high nutrients or both.

 

[AquaRick]

+1 Cyano.

 

[melosu58]

We have a great article on it in our sw articles section.

 

[Iceman72]

Thanks guys. I need to get some not so powerful power heads for that side. I have dual 1800 in my 55g tank and it blows my sand like crazy. I will check out the article.