Okay I think I understand how the heating tape works. Will this thermostat work with it? http://mgreptiles.com/ZOOSTAT.html and what are the disadvantages of this one compared to the others? and for the flex watt this is what i should be getting correct? http://mgreptiles.com/flexwatt.html and is there any differences when buying, how many feet of it do you think i should buy for about a 4 foot rack with 5 tubs going down?