Putting in a airpump will do nothing but move water around. It is the moving of the water to the surface that oxyganates the water, not the air from the airstone. Running another powerhead will acomplish the same thing as an airpump without all of the saltspray One way to kill it off is to use red slime remover. Stuff works great, but it will make your skimmer go crazy and you want to do water changes after all the algae is gone which should be within 48 hours. I used it on a reef before and the only side effect was the skimmer going nuts as it pulled out all of the algae that was wiped out. Unless you improve water quality though it will come right back eventually. I personnaly would increase water flow, use a mechanical filter, and take a soft brush and wipe it off the rocks. The mechanical filter should catch alot of it. Also when you water change suck it off as you remove water. Make sure to use ro/di water. You can get water usually from water machines and the water is as pue as you could want.