painting the inside of an overflow (with solution!)

[lastlight]

My tank builder gave me the remaining paint from when he painted the back of my tank black. It is an acrylic latex. I used this inside my external overflow to hide all my plumbing but after a few days of water circulation it started to peel in several lrge sheets.

Can someone recommend a material/piant to do this? I'd prefer a paint so the space looks the same as my tank back. A piece of acrylic plastic would work but def look quite a bit different from the rest of the tank.

- needs to be marine safe when it's dried
- not peel off glass
- prefer something i can brush on. getting in the overflow now is by brush only. spray paint would be VERY tough.

Thanks folks.