Well, either way it will need to be hooked up to a thermostat. Plastic will not melt at 95 degrees, so you shouldn't have to worry about that. Just place the UTH on the bottom of the tub. If you don't want to peel the sticker off it and permanently adhere it to the tub, you can tape it on with aluminum tape. I'd put the thermometer and thermostat probes under the substrate directly about the UTH. That way, you can get a good idea of what the temps are through the tub and closer to your ball.