Welcome to the world of having no money anymore.


Take out all of the corals, rock and fish. Scrap the water (it will be full of nitrates and phosphates since there is an algea problem) except for enough to transport the stuff. Get a bristle brush and get rid of all of the algea on the rocks and in the tank. Pick up some instant ocean mix and make up a new batch. Check and double check the SG and bring it to the correct temp before using it.
Pick up some red leg hermits and nassarius snails. You can also get asto and turbo snails. Don't get a mithrax crab no matter what anyone tells you. They eat algea but also eat coral and will munch fish.
Change out the bulbs. The spectrum shifts after a few months and can cause algea problems.
Get a protein skimmer (do not get the crap ones with air stones. Go with a Berlin or a Remora). Make sure it is a counter current venturi or spray induction and rated for at least a 100 gallon tank (trust me on this one, they WAY overate the skimmers on the market for what size tank they can handle). Stay away form backpacks. They are bubble facotries and overflow. Smae with Knop skimmers and the various knock off types of the same design.
Get a powerhead to provide a current in the tank. It helps the corals and algea is not fond of the turbulence.

Any questions, let me know. I have found out the hard way over the years just what works and what doesn't.