Red in sand

[mouse03245]

Ok...Got our aqua c last week and 2 maxi 1200's a few weeks ago. I am now noticing red spots in our sand.Not too sure what it is. We did a water change this past weekend and cant figure out what is causing it. All our tests are perfect except nitrate which is at 20ppm's.would that cause it? any help would be greatly appreciated. Thanx in advance !

 

[philgmiami]

Originally Posted by mouse03245
Ok...Got our aqua c last week and 2 maxi 1200's a few weeks ago. I am now noticing red spots in our sand.Not too sure what it is. We did a water change this past weekend and cant figure out what is causing it. All our tests are perfect except nitrate which is at 20ppm's.would that cause it? any help would be greatly appreciated. Thanx in advance !
i have the same thing in my sand. its coriline :yes: .its a sign of a healthy tank

 

[viper_930]

Coraline doesn't normally grow on the sand.
Are the red spots soft? I'm thinking it's red slime algea, aka cyanobacteria.
Cyanobacteria

 

[bigarn]

I'm thinking the same thing.