I am currently working on building a steralite tub rack for my 4 yearlings that will also be able to house future hatchlings. I will be putting them in 28qt tubs currently but I plan to move the two females into 41 qt tubs in the future with additional 12 qt tubs for hatchlings. I have been having a hard time finding the answers for what width and where to place the heat tape. I am uncertain if at 6" width heat tape on the wall side of the length of each tub will be sufficient, or if I should place a 3" strip of tape underneath the same side instead. Would the wall mounted tape work for all sizes? Would the 3" under tank strips not provide enough of a gradient for the 12qt tubs? Any suggestions or personal experience would be greatly appreciated.