I can't get the temps high enough!

I have my BP and my CA king in 110 quart sterlite tubs. Each is about 2 and a half feet long, and one foot tall. I cannot get the temps right. Its about 76 degrees in each cage. I need it to be about 85-86 in both of them. I'm thinking about just going to wal-mart and picking up new tubs about the same length, but not as tall so it won't have to hold as much heat. Will this work?

Thanks!

That could work, or you could get a slightly larger under the tank heat mat, or flex watt, depending on what you use. Or, if it is possible, you could get a room space heater and use that to help.

Well seeing as large adult female BP's do perfectly in 41qt tubs,males in 28qt. try them

Where are you measuring the temps? In the air or on the substrate? If you are heating with only flexwatt and are measuring air temps, it could actually be too hot for your snakes. Measure the temperature on the substrate where the snakes belly is resting.