Green rocks

[backpack]

My rocks have a realy green look to them. Never noticed it till I put one in the sump. Is this due to po4? I only test for po3 and it seems low.

 

[twelvefive]

I'm pretty sure it's just a form of coraline algae. Comes in green, blue, red, yellow, pink, and purple.

 

[Reefing Madness]

The greens on the rock tend to be a bit to much phosphates in the water. You'll know the Coralline pattern, if its just growing all over the rock, you'll want to test for phosphates.

 

[mike007]

+ 1 You need to make sure your nitrate level is in check and phosphates. Overfeeding is the most common cause of algae problems which cause exccess nutrients in water column.