Mantis:
If it is only $40 then it is a good deal and you may not want to pass it up. Running it for 1-2h a day however does not do you much good (especially on a 250). A 25W at 150 gph should produce a 100% kill curve on on single pass for parasites, algae, bacteria, benificial plankton, etc., but I truly do not see a point of running it a couple of hours a day. The UV bulb also is not a bulb that can take many cold starts and the effective life (which is short anyway) will be greatly reduced. As I said I have a UV filter and choose to run it if and only if something doesn't go right or seem right. It has saved me a few times however and I do keep it as a weapon in my arsenal.
Tim