Right now I'm using 4'' heat tape on my breeders rack. I have two stripes side by side running down one foot, so my heating area is 8'' by 12''. I'm about to build a new rack which will hold 58 qt (23L x 17w x 13h) tubs I was thinking of running a single 4'' strip along the back as belly heat. however i was looking online and saw 3'' is a little cheaper so I could get more for my money. I'm a little worried that the ambient temps won't be high enough and I won't cover enough area with 3''. Also I can't solder very well, does anyone have a better way to connect heat tape besides solder and the expensive heat tape connectors? Let me know what you guys use on your racks and what you think thanks