I have been using a UV for at least 10 years, never had ich or any parasites in my tanks, and my fish have always been in perfect shape. I have a 25W Aqua Ultraviolet on my 90 gallon reef (probably a little overkill as I took it off my 180).
I have yet to be able to afford a nice one, I can tell you from experience that even a cheap one will help with algae a bit. I put a cheap mean green machine in a 36 bowfront and also in a biocube for a bit and the water cleared up great. For parasite control you have got to spend some serious money.
There is a nice discussion about the scientific side of it at the top of the forum that can offer some nice background.
rk4435;943984 wrote: I have yet to be able to afford a nice one, I can tell you from experience that even a cheap one will help with algae a bit. I put a cheap mean green machine in a 36 bowfront and also in a biocube for a bit and the water cleared up great. For parasite control you have got to spend some serious money.
There is a nice discussion about the scientific side of it at the top of the forum that can offer some nice background.