Dry rock bubble algae.

[NU-2reef]

Nothing wrong with dry rock. Just needs time to get live. Because it lacks beneficial bacteria the rock has no way to deal with the ditritus that settles in the pores and becomes a nutrient factory. That would be why algae is more prevelant to dry rock , just an easier place to thrive on nutrients. Dry rock is better for new tanks and people with patience to wait several months for the bacteria to mature and establish itself.

I used 90% dry rock in my new tank that has been running since nov2011. Still no coral or fish just mb7 and reef fuel. The other 10% is live rock and sand from a well established system. Now my rock is just as live as any with lots of coralline and zero pests.