UTH - Under tank heaters
Put these under each tub, it's all you really need. No lights required.
Heat Tape
Stick a few pieces of tape to the bottom and/or sides.
Why do you say no light is required? Will the tape on its own keep the Hot Side 90-94 and cool side 82-84? I'm new to owning a BP and he is in a Plastic container. I was told know actual light is needed but a Red Heat bulb will be needed.