Tanks to Tubs

[sho220]

http://www.amazon.com/Sterilite-4-Sh...ef=pd_sim_hg_1

Wait, could I use this to put the heat tape on and the tubs sit on it, as opposed to a full rack for the time being? With heat tape on three of the shelves?
How deep should the tubs be for a 41qt?

I use the same type of shelf for my hatchling rack. Works fine. The only downside is that it's not as space efficient as a dedicated rack. Gets the job done just fine though.