Which Hang-on-tank UV sterilizer would you recommend?

[Seafan]

I am looking for a Hang-on-tank UV sterilizer to use on a quarantine tank of 10g-50g. I wonder why most UV sterilizer I see in the catalogs are in-line? Are they easy to convert to be hung on the back of a tank? The only Hang-on-tank type I found is Angstrom 2537. How is this brand UV sterilizers? Are they effective and easy to maintain/clean? They list 4W for up to 75g and 8W for up to 150g. Are they really that strong to work on tanks as large as 150 gallon?
Thanks.

[David]

I have a 15 watt hang on UV by Coralife, quartz sleve and nice design. I used a rio 800. I haven't used it for a long time but I figure it's a good thing to have around. I think it was only around $100 from lfs so mo should be pretty reasonable.

[fishrule]

Seafan, I have been told that the best way to kill bacteria/parasites is with a in-line, that way you get better turnover. The best I have seen is emperor aquatics. If you have a uv on a separate pump, it will not be able to kill enough bacteria/parasites. You can stand this uv on it's end, but won't hang on the tank.

[ADS]

I use the CSL double helix on my clam systems. They are hang-on types. I run my inflow thru the 36W model since the vats are low flow for the clams. A small powerhead could easily run them. The bulbs are long life. Solid construction. 9W for 50g tank, 18W for 100g, 36W for 250g. They are cheaper than any inline <<$100.
Adam