Does your tank see daylight? if it does then you should have the tank covered (blanket) and try limiting the light on the tank to 1/2 hour, or use a smaller incandescent light to reduce the algae growth.. it took my tank 5 days with very little light to clear up a lot (i can see through it end to end.)
Edit, also slow down with the water changes, if your tap contains high phosphates then you could be feeding it more then controlling it.
watch you nitrate/ammonia and nitrite levels and only change the water if they get up in range.
also, try to add an air stone, it will help remove CO2
which can build up with a massive die off of algae.
120 Gal SW, 150lbs Prem. Fiji, 23Gal Sump, 2x250w 15K MH, 4x65w Actinic
3 x Halichoeres Chrysus (1 surfed), 3 x Nemateleotris magnifica, 1 x Centropyge bicolor, 11 x Scarlet Hermits, 6 x Zebra Hermits, 40 x Astrea Snails, 6 x Nassarius Snails, 3 x Cerith Snails