thanks for the replies.

For the colubrids, the 5-inch is alot of space, and i think they would mind the extra space.

Im more concern that the 5-inch would be too short for my Ball Pythons. i got 10 currently. Reason i switching to racks, I hope this will be the final tub for them, i mean, hope they will live in the "soon to be built" racks until the end of their life, including breeding purpose. Currently, most of them are in 22 x 14 x 4 inch tubs with lids.

so, do i go ahead and buy those 30 inch x 18 inch x 5 inch tubs? or find a tub with a couple of inches more on the height?