Is it just me that's missing something here? How is a UV sterilizer going to have a significant effect on water clarity? Also, I hate to be lazy, but if there's something in that 6 page thread on xenia that is supposed to enlighten us, could you please give us a quote, a page number, or something?
As for the rest of the responses, I agree. One thing I also do is use a canister filter with a 1 micron filter about once a month. It probably won't help much with severely discolored water, but it's a good way to remove a lot of fine particles from the water that can affect clarity. Paul B (probably our most experienced guy here) does basically the same thing with a diatom filter. I also run carbon, which as tkeracer pointed out, can be very effective for discolored water.