Originally Posted by Robert123
Yea. It prevents unwanted alge
I wouldn't trust it, those algae products do more harm than good. They have a lot of chemicals in them that can kill or poison your fish.
Depending on what algae it is you can get rid of it with black-outs, scrubbing it off, Excel spot treatments or, if you are willing to, nerite snails or Amano shrimp.