I would raise your chlorine levels to 12PPM FC and run your filter 24x7 backwashing every few days until the algae bloom is cleared up. You can also add Polyquat 60% to assist with the clean up. The best price I've seen on Polyquat is from Leslies Pool Supplies and it's called Pooltrine.

http://www.lesliespool.com/shopping/...word=pooltrine

Physically getting into the pool with an adequate wall brush will be necessary to completely remove the bloom. Once you've had an algae bloom you will have to be diligent about keeping it at bay or it will return.