Truth be told unless you have an algae problem don't add anything to the tank. If you aren't showing signs of algae you can simply buy a snail(which would do well in a tank that size) if you are really worried about it. You don't want to mess with the filter though, everything in there is beneficial to your tank.
Now if your tank is turning green then I would look into doing soemhting about it. Sorry I can't really comment on this product though, never used it