Red spots on rock

[mihadj]

I am in the process of starting a new tank. I have placed 50 Kg (110 lbs) of dry rock in the tank and my plan is to add a few Kilograms of cured live rock. Before add the live rock I have noticed many red spots on the rock (see the picture below). Some spots existed on the rocks but multiplied when added in the aquarium. They are hard and can not be easily scratced away. Does anybody know what they are? Should I remove them before proceed with the addition of live rock? I would appreciate your help.


http://reefcentral.com/gallery/data/500/113141IMG_3776.JPG

[dwd5813]

coralline algae. adds a nice coloration to the tank, imo. people pay money for rocks covered in the stuff. the fact it's spreading is a good sign.

[mihadj]

Thanks for your reply. But how can coralline algae survive on dry rock? Rocks were out our water for a lot of time, maybe weeks or months.

[wmilas]

The spores can survive out of the water... they reactive when wet.