I don't currently dose vodka. I say that in the interest of full disclosure. What I propose is a temporary technique to get rid of your nutrient problem, not necessarily a permenantly solution. That said, look up vodka dosing. It changed my reefing life. Don't be as tentative as the instructions suggest. Start at half a ml and increase by half a week until you find your max, then halve it. If not vodka, try vinegar. I have no experience with it, but lots of folks claim it is even better. You need to get rid of the nutrients in your tank so you can settle into a long term maintainable mode. Doing so with GFO requires constant changing of messy GFO. In practice, people give up. Carbon dose. Trust me, carbon dosing will help you make the tank manageable.