i recently painted mine, talked to they guy at home depot. he suggested behr paint, and it worked really well. 4 coats of a dark blue and came out well
rustoleum latex paint in any color of your choice. ( i always get semi gloss and some get flat) grab a small roller and paint tray and start your 5 coat process. your tank eventually will be covered in coralline algae one day anyways...
I suggest car tint... my 72g has 5% in the back, though i did a horrible job, it wasn't hard to do.
it makes sense, you can see in from the back since the lighting shines in the tank, but you can't see past the tank because theres less light back there.