UV units will only clear water by killing and flocculating free floating algae. In aquaria they are more commonly used to kill off parasites and bacteria floating in the water and prevent them re-infecting other fish. They are especially handy in centralised systems. Apparently any damage to fish does heal much more quickly when in a UV filtered tank.
You need to establish what is causing your lack of clarity. If it's algae then the UV would work, but if it's tannins from wood then it won't do a thing and you need to use carbon or Seachem's Purigen and if it's small particles floating in the water you need to put some fine filter floss or similar fine media in the filter to trap them.
The UV would not effect water parameters in any other way IME.