straight up plywood as shelf

i have a 3 shelf rack, just setting tubs with UTHs under them, the plywood should be good right, of course a thermostat is in use

Plywood is a cheap bendable wood. Eventually it will begin to show ware and tear. I would guess sagging be the first problem you will begin with.

Pictures?

not yet, by the way it only has 1 tub on each shelf, 2 31 qts, bottem has 74, underbed. but aside from benddng no problems, i talked to peeps on reptic zone and got same answers, just pposting it here to see everybodys, response. not worried about wear, at moment, this is just a 4-6 month fix, till i can get some real racks, the boaphile killed the wallet for a while