pd I bought a 1500 watt water heater element at home depot drilled a 1 1/4" hole about 4'' up from the bottom of a plastic storage bin, the element will seal up against the tub on the outside. then i used a PVC threaded coupler on the inside of the tub to hold the element tight to the wall of the tub. you also want to use high temp silicone where the coupler seals against the tub. Then mount a lower thermostat to the side of the tub and use the silicone where the two bolts mount thru the tub. I bought a extension cord and wired the element to the thermostat then from the thermostat about a 5 foot lead that plugs into the outlet. works perfect. $25.00 to build an about 30 minutes. key is never let the element get above the water when plugged in or it will burn up.