Extra Filter for UV position in tank

When I kept coldwater fish in my Juwel Rio 400ltr tank, I supplemented the
built-in internal filter with a Rena XP3 so I could use a UV.

I altered the flap with a saw so I had the XP3 intake alongside the
internal, and the spraybar at the other end.

I've just kept it the same now I have trops in for the past year.

I'm now about to to do the same with my Rio 240ltr (also has a built-in
filter) a XP2 and a UV, but wondered if I might be better siting the inlet
halfway along the tank, or would this leave areas of water un "UV-ed" ?

Peter