???I traded this 55 gallon for a smaller tank including stand, light etc. the only thing is this film on the inside of the tank scattered around.It looks like when you spray windex on the glass in your car and don't wipe it>Its on the inside of the tank under the water and i keep saying i am going to try razor blades on it but i tried to scrub it off with no luck.What do you guys think it is and how to get rid of it???