My experience in exactly as Smite states it. Blackouts don't work and good housekeeping and physical removal are needed. He has a good list. If you search R2R for Green Hair Algae GHA you will gets a ton of threads where people are dealing with this problem. Most snails and other CUC members won't eat long strands of algae but seem to eat it if you have done some physical removal. I'll add two things:
-You need a good clean up crew of snails and hermit, maybe some algae eating fish like tangs, angels or bennies. Every LFS will tell you this or that critter will take care of it but there is no magical creature that works for everyone in every tank
-A good way to combat GHA trapping detritus is to use a turkey baster or a power head to blow the detritus out of the GHA to get it captured and removed in your filter media.
-Physical removal means getting out of the tank and try to not generate a lot of strands to float around and spread to other areas of the tank. I use a toothbrush on the end of a small siphon going into my filter sock and it works for me. You have it on your sand so I would just siphon that sand out of the tank
