I built my first rack on saturday and it came out beautifully, flexwatt is wired, installed and I have the thermostat set up, temps are regulated just fine, humidity is fine, however... I built a 6 shelf rack and the thermostat I have only has availability to plug 3 cords in, I tried using a 4ft extension cord to hook up all of them and the 2 strips connected directly to the thermostat are working, but not the strips connected to the thermo by the extension cord, so I guess my question is how do I get all 6 shelves heated successfully on one thermostat? Thanks