Hi Melanie,

I'm glad to see you taking the time and effort to do things right.

First off, an aquarium isn't an ideal setting for a snake as it can be very difficult to regulate the temps and humidity. Not impossible, but difficult.

A better alternative would be a PVC cage that is used specifically for snakes. You can find many companies such as Reptile Basics, Boaphile Plastics, or Animal Plastics that make such cages. These provide an environment that is easy to heat, keeps the humidity in, easy to clean, and is visually appealing. You can use a Sterilite or Rubbermaid bin for the same results, but many people don't like the look of them especially if they're only going to keep one or two snakes.

As far as your temperature control, the Repti-Temp Rheostat didn't have a probe because rheostats only control the the current to the heating device. It's essentially a "dimmer" whereas a thermostat will adjust the current in order to maintain a specific temperature. The most common pet store brand is the Zoo Med, unfortunately they are rather cheap and have been known to fail relatively often. A better alternative would be to purchase a reliable thermostat such as the Johnson, Ranco, Helix, or Herpstat. The latter two are proporational thermostat which are essentially a rheostat and thermostat combined and are a little more expensive.

As far as heating, if you stick with an aquarium you might be better off with the UTH on one side and the lamp over the other side. The lamp would then be used to heat the air space in the cage and the UTH would be used to provide a stable belly temp for your snake.

Good luck!