It gets rid all of the algae IN the water but NOT on the glass but you can use a pleco or fei fung to clean them up easily. Don't spend $ on the cheap china uv. It is just a waste of money. Go for good brand like aqua, coralife and so on. Remember to use the right watts and right size pump for your tank. Too weak or too strong power won't do anything help except wasting electric. You can google their manual, different manufactures have different specs and instructions. Beside getting rid of algae and keeping the water super clear, uv can also keep your tank healthy and prevent a lot of disease in the future. VERY VERY WELL WORTH THE $ IMO.
I like aqua brand the most (the WHITE classic one not the black version). It is a very solid and well built piece but kinda pricy. Well you pay for what you get.