Something to consider about tubs is this. Sterilite and Rubbermaid routinely change their designs and dimensions, so if you need to add/replace tubs at a later time, they may not fit. Iris doesn't change their tubs, so there is consistency with them. Plus, if you decide to build another 32qt rack in the future, you could use the same rack design without having to customize it to whatever tub style you have at the time. You can order Iris tubs from ReptileTubs.com.