The ucv can PREVENT PARASITES AND FURTHER GROWTH, but its not going to solve an existing problem, it would definatly benefit the spread of it but it will not cure. I run a 9watt uvc 220gph on my 90gal and never had parasites so to me its very very effective! And the bulb is fine untill it burns out, roughly in a year and 10-20$ replacement!
I would think if its ick or has an egg or larvae stage that the uv would suck it up and run it past the bulb killing it as long as its good quality and uv-C then it should stop some to most eggs or what have u but no telling that cuz u havent said what it is....
What he said^^^^+huge water changes inaccordance with treatment
if you would have spent $30 on prazi powder you may have had better luck and got much more. prazi is only effective on certain bugs, mainly tapes and flukes (barely these days). Metro will get the nematodes and flagellates.