i get this really hard to remove algae that grows on my front glass it is green and hard like rock it covers the galss sometimes somone has tried to remove it before by using a pice of steal wool it did remove it but the glass is all messed up so i need to replace it pretty soon but i know it is going to grow again so how do i remove it from the front glass i am not worried about it growing on the other glass it is just to remove it from the front glass