Agree with everything above.
GFO will work well on phosphates too if you run in a reactor. Carbon dosing works well to keep things under control. If you use GFO in a reactor, I think a good target would be for your tank to be stable at <0.1ppm PO4 by easter 2016. Read up on the topics Jason posted above, he's done you a great favor with those links.
You could use lanthanim chloride a few times to get the levels down quicker, but you'll still want to use GFO and/or carbon dosing later to maintain levels where you want to be.
Personally I'd stick with
0] Cut down feeding. Do a few days lights out. Limit photo period to 8 hrs a day.
1] GFO in a reactor
2] Choose your PO4 test kit and measure every week or two
3] Manually remove the algae when you do water changes
4] Read up on carbon dosing decide if you want that or not
Shoot for pristine water by easter. If you get there sooner, give yourself a massive pat on the back. Slow and steady wins this race
You could try take a picture once a week if you like. That helps show that things really are getting better. Sometimes it feels like progress is very slow but you'll get there.
-droog