Can I just ask what you all do to keep you tank glass clean? I have got small round dotty marks of dark green gunk on the inside of my tank. I wipe off the normal muck with a bit of sponge, but this doesnt budge and I dont want to scratch the glass. I have heard good things about the magnetic cleaners, but have also read that they can cause scratches, so what do you all do - get the Windolene out?? :lol: