I have my first acrylic tank, a pico, and I can't seem to get the sides clean. I have a mag-float-type cleaner, a nibble nano, and it works amazing on my glass tanks but does little on the acrylic. I've tried a paper towel and that was a bust. Short of a razor blade I'm out of ideas. A razor blade isn't really an idea, but I'm going crazy not being able to see in well. It was already fairly scratched when I bought it, so my main concern is just cleaning the algae so I can see my frags. It's my frag tank so I'm not too concerned with scratches. What do you use?