I highly recommend going with one at the Ocean Clear canister filters. They are modular, come in all different types including UV sterilization, and can connect to almost any choice of pumps (I recommend the Little Giant pumps). They can be plumbed quite easily using flexible Poly pipe. Keep in mind that they are used professionally. I currently have two 300 gallon Rubbermaid tubs, one with alligators and one with spiny softshell turtles. On both of them I have the intake to the pump hooked up to the bulkhead fitting of the tub, since water is pushing itself into the pump, the pump does no work on the suction line. The pump and goes to an Ocean Clear pleated filter. On the softshell turtles I also have a Poly bead filter for biological filtration.
I can't say why ultraviolet sterilization is not use more frequently, especially in turtles, other than the fact that they can be ridiculously expensive to maintain. The bulbs can easily cost $40 apiece!
If you were to get a pump with a pleated filter and Poly bead filter, you could easily be looking at $450 worth of equipment. But I can't emphasize enough that these are quality materials that you will not have to replace for a decade or so. Given the extremely long life span of turtles in general, thinking long-term obviously has its advantages.
http://www.austinsturtlepage.com/Articles/filtration.htm
click here for the link
-----
...the oldest task in human history: to live on a piece of land without spoiling it."
Aldo Leopold (1938)
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)