OK I am new as a BP owner (18 mo.s) I keep hearing people talking about flexwatt/heat tape.I have seen it on website for sale. My question is how do you use it?! Specifically,I have 5 BP in separate Sterilite/rubbermaid containers,do I use 5 stips of tape with 1,2 thermostats or do you need a seperat thermostat for each tape strip?! Help!