The photos are not very clear, but it looks like you have two types of algae, a soft "feathery" type, and some of the dreaded bryopsis bubble algae. The feathery soft alga will disappear quickly if you introduce a small urchin. Not sure of your tank size, but if it's large enough one of the Tang species would also eat it. The bubble algae id another matter - it is *very* difficult to eradicate, as nothing we normally keep in our tanks will eat it. Best move (and yes, I know it's painful...) is to remove all the infected rock and let them dry out completely in the sun for a few days (or microwave them...). Also keep a sharp lookout for new growth, and react quickly if you see any - small isolated bubbles can be killed by boiling them with a magnifying glass in the sun (also works well to kill isolated aiptasia) - you will obviously have to remove the rock from the tank to do this...
Hennie