uv sterilizers

having a huge and growing free floating alge problem so im looking at a uv
sterilizer for my solution has anyone else used these costly items? im going
to use one becuase i had this hit my tank before while i was on vacation and
it wipped out my tank except a pleco so iwrote that off as a 300$ fish loss
not to mention 2 years of raising the fish so i am pretty warry water
changes and filter changes dont work
its a 155 gallon bowfront runing grow lights 12 hours a day