Should work as long as you us a divider if you try to got to a smaller tub here is what you might run into . Depending on the size differance. The smaller tubs will have less air to heat they will heat up the quickest. If the probe is placed on the substrate of the smaller tubs then your thermostat will cut off before the larger tub heats up. and vise virsa. If the probe is in the larger tub then the smaller tubs will heat up to hot. Many rack makers deal with this by figuring the total surface area of the tub in contact with the Flexwatt. This is why you see multi sized rack systems with some of the smaller tubs turned sideways. And also why some makers don't offer a single heating unit, multi size system. Many makes do offer a divider so your good to go. Let me know how it turns out.