Do you have a Clean up crew in there? Snails and crabs will eat algea if it is at a managable level. If it is too tall they will not touch it. You will need to manually remaove it first.
The thing you need to find is where it is coming from. Nitrates, phosphates, and old lightining are some possibilities. If you are using bad water 2 of the things listed can come from that.
I would not recomend cutting the lights. It will just come back once they are turned on again. You need to find the source and fix that.
I have bataled the demonic Hair. The nitrates in my old tank were the problem. Due to the fact I did not do regular water changes and fed my fish alot (big ol' naso tang) they were allowed to build up. Once I started the new 180 and followed a schedule they have since disapperead. I added 100 blues 100 scarlets and 100 snails to keep all algea under control and have never been happier. I have not seen any spots since then.
Once you get all your maintance on schedule and you add the apporite number of clean up critters, your tank will pretty much take care of itself. The most beautifull tanks I have seen have been the ones that have the least amount of work going on to them. Minimal is the key! Let the tank mates do all the work. You just supply the water!
Good Luck