Wondering : Are you using 41quart containers ?

I'm about to build my 2nd rack .... it'll be a 41qt. breeder/larger BP rack to compliment my 9 slot 28qt. one.

Question: Wondering why you'd not put 100% of the heat tape under each tub rather than not utilize what looks like about 8"-10" of $4.00/ft. tape on the sides....when there is no actual contact between the side and the tape? Seems as though you'd get much less heat loss that way. You could also put a 1 foot wide hardboard up to retain some of the side heat.... and still have 66% of the side open in order to give good lighting and visibility to your collection.

RALLY like your BP rack and I see what looks like many extra boards at the bottom, so you seem to be set for some serious expansion to your collection in the near future. WELL DONE!