Painting back wall.

Whatever route you take, make sure you wash the surface with denatured alcohol before applying any sticker material or doing any painting. You'll have a much better outcome with a clean surface.

 

heres my idea for the new tank.. take some purple, pink, dark red purple, etc.. all the corraline colors, empty the paint from each can into a jar (turn can upside down, release propellant, then poke two holes in top oppisite each other). then using an eye dropper draw up colors and drip them onto the back. let colors dry some then use another color. youll have a nice corralline covered background without having to wait. You guys can call it "the duck method" lol.

 

home depot has eco freindly paint , seal the tank turn off air pumps , run some carbon . but imo i wouldnt paint a full tank not worth losing anything get a background store bought or diy