@kingdomall, respectfully and with care, there are several flags here. That tub is huge. A CHE on a tub is asking for disaster, and without a thermostat, a dimmer is a secondary concern. None of these issues alone are deal breakers, but all three together is just a huge hurdle for results that are likely to be disappointing.

I am sure somehow success *can* be achieved in the scenario you're chasing, but I wouldn't recommend it.

The following slight, and inexpensive tweaks will make all the difference:
- use a smaller 32 or 41 quartz tub with a lower clearance. This will aid in humidity and temperature retention.
- use two heat pads, or get even less expensive heat tape and solder up two pads. One for your hot temp, and one for the cool temp.
- Use a thermostat on both. Disregard the dimmer and CHE altogether.

Best of luck.