good to now I was looking inot these as well have any idea what the largest is rated for? gph and tank size? also I thought the ones with the UV had a bigger wattage availible? I know they have the one with the 9watt but I also thought they had one with a larger wattage than that? any extra helps I am sure, and I am sure they took into account of the gph of the filter in comparison to the uv light after all they made both rite? good to know it was a JBJ and marineland product?