Either a 28 quart tub, or a 20 gallon tank would be fine. I wish you would be a little more specific when asking. Are you making your own enclosure or buying one?!?!?
6.5.15 Animals
1.2 Pomeranian's
0.1.15 Tropical Fish 2.2 Snakes:
0.1 2009 100% Het Piebald
0.1 Normal
1.0 Green Tree Python
1.0 Brazilian Rainbow Boa
Then you need a Vison Cage Model #221. I own one right now and its about 24 inches wide, 29 inches deep, and 12 inches high. It's perfect for a larger ball python when you put 2 hides and a water bowl in there. Then when they get bigger you can just take out a hide. I've had anywhere from a 500 gram to a 2500 gram ball python in this cage with no feeding issues or shedding issues.
6.5.15 Animals
1.2 Pomeranian's
0.1.15 Tropical Fish 2.2 Snakes:
0.1 2009 100% Het Piebald
0.1 Normal
1.0 Green Tree Python
1.0 Brazilian Rainbow Boa