If I have 3 uth's for my tubs, can I put all 3 on a thermostat? One is a higher wattage but I would use the probe on the lower wattage uth's. The diff in wattage is only 2 watts. Same brand etc. Will that be alright or will it cause issues? The total wattage of all 3 uth's is under the allowed wattage for the thermostat as well.