tub not a option, tank size?

[babyknees]

Then tub will be your option not a glass tank that loses heat faster than plastic does.

Cold rooms tanks dont do well unless a lot of effort and time go into it. Plastic tubs will help hold in the heat and humidity with simple UTH covering 50% of the bottom.

x2 Go with the tub...you'll go insane trying to heat a tank.