Well my so called Bacteria bloom has turned into or always was green water. I have been unable to find a UV light to borrow locally so I guess I better buy one. I have seen on some site selling UV sterilizers that you don't need a super powerful one to kill green water. So I was wondering if anyone hear know what is the smallest one I can get away with for my 120gal tank. I hate to pay a couple hundred dollars from something that I will only use for a few days or weeks.