You can do a seaweed sump on the cheap if you have space. Easiest if your tank is drilled, but you could use a hang on overflow too. A Rubbermaid stock tank $75, a couple of 150 watt halogen parking lot lights 2X$20 and a pump $100 to get the water back to the tank. I toss beach ball sized bunches of cheato every month. My LFS wont take anymore until they sell what the have!
Tom
Tom