Pump for a UV Sterilizer

So my friend recently sold me a UV sterilizer for cheap because it needs a new bulb and the pump for it broke. Getting a new bulb is easy, but the pump thing is proving harder than expected. I dont want a super strong one, just one strong enough to ...well, put the water through the sterilizer.

I found this one:
http://www.petsolutions.com/C/Pumps-For-Pond-Fountains/I/ViaAqua-Water-Pumps.aspx

but I dont know what size I should get. I only have a 40 gallon. Opinions on size? Opinions on this particular pump?

I have ViaAqua pumps. They are cheap, but they do a decent job (at least the smaller ones anyway). The bigger ViaAqua pumps really heat up the water, and I had one large one fail on me. I think you'd be fine with one, though. I currently use two ViaAqua pumps (one for my reactor and the other for my water changes), and they do fine.

As for what size, it depends on what your UV sterilizer recommends. Post the specs on your sterilizer, and I can try to help. Probably if you Google the type of sterilizer, it will tell you the recommended gph, and then you can pick an appropriate pump.

I usually use a maxi1200 or 900 for mine. As Samantha said, we need the specs on the sterilizer and if possible, a pic to really help

I found a website that says 120 will be the lowest gph reccommended, but I found one from the current-usa website that reccommended 200gph. ViaAqua pumps have a 190gph. Will that do?

It's a 8W Current-USA Gamma UV Sterilizer. As far as I can tell, Current-USA no longer sells them and I can't find a ton of info on them. I did find the manual though...

http://www.current-usa.com/files/GammaUVAquarium_Updated3-08.pdf

If you've found that it should be greater than 120gph and 200gph is recommended, I think you're fine going with a pump at 190gph.

From what I found Googling, though, the ViaAqua 480 is rated exactly at 200gph.