how to keep back of tank clean?

I have been trying to figure out a solution on how to keep clean the back glass of my tank, primarily between the overflows. It's a 220 that is inset into the wall and the outside back of the tank was spray painted black when installed. It's essentially impossible to get a razor blade to it and the coralline algae of course has grown and encrusted, which I find very unsightly. I have heard of (but never seen) gluing green star polyps for example on the back glass. Has anyone done this and if so, I'd love to see a pix. Are there any other solutions???

 

Plating montipora will grow on the glass as well. I do know there was a thread recently about GSP on the back glass and it had some pictures from a couple tanks but I can't remember what the thread was called.

 

http://www.3reef.com/threads/new-additions-green-star-polyps-purple-gorgonian.155191/

^^ this is the thread. There are also some warmings in there about gsp. I'm considering something similar but I'm a little concerned about overgrowth.

 

You don't clean back glass. Let it grow

 

I just glued gsp to my back glass. Hasn't come out in 3 days

 

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