These dont get great reviews from what I have read. For the price I would get the "Green Killing Machine"
UV Sterilizer from Petsmart. Its about the same price and works wonderful for green water. It is large though and sits in the tank. UV lights also come in hang on back and inline with a
canister filter. These two options provide a much less crowded tank and if you are obsessed with making your tank look natural (as I am) the in tank ones are a little ugly to look at. I only use mine when needed (disease and algae problems) If you are getting one and money is not an object get one that isn't in the tank.