for sure that would be the best idea just because you have it there does not mean you have to use it all the time, but, I know other people that have them in place to use them when need dictates.tuggerd;3182657; said:I have a uv light for my 3,000 gallon pond that I used for the first year. I havn't used it now for about 8 months and the water is crystal clear. Yes I did need it for the first 6 months. I suppose that once my filter matured it took care of the floating algae. I'm thinking about putting a uv light in one of the waterfall entrances for a while. Just to give the water clarity a little boost.