If you have a little fish pond and don't have a UV pond light, you will have algae. Algae totally detracts from the whole pond thing. I found and rebuilt a very old little rock pond and bought this light to keep it nice, and it does. I have a similar, but bigger, light in my much larger fish pond and it has kept it clean for about ten years now. That pond is big enough and has so much established fish, insect, plant and gunk life that it is almost self-maintaining. Even though it is normally recommended that you change the bulb to maintain that other-world weird glow, I found that every two years is enough.A small pond, however, cannot be expected to get that perfect natural balance and so this bulb may have to be replaced every year. We will see.Note that the transformer is separate from the body of the light, so that makes it much easier to mount and prevents it from shorting out if the main tube part springs a leak. This is a good feature. Also, you can buy all the seals, tubes, bulbs, etc. to maintain the device. It is not a throwaway item and that is a good thing.The part I didn't like was the description of "adapters" for the hose hook-up. This is misleading. There are simply built-in 3/4" barbed projections and only 3/4" hose will fit. I had to rig up adapters using 3/4 hose and 3/4 to 1/2" reducers made for drip systems (I think). The pump I bought had three screw-in nipples to fit three sizes of hose. THAT is an adaptor.Anyway, while they don't give these away and the bulbs are not cheap either, this is a quality unit and a must-have device for your pond enjoyment.
Rating: [3 of 5 Stars!]