How do you not know which stat you have?
Dont place in with them, if they move it CYA readings go down the drain, Add another level if you can and place a "fake" tub in that case that is empty, drill a hole and place probe in that (always leave empty) and you should be fine, i did this in the begging with my 7 high rack, with only 6 snakes, used middlish tub as a "temp reader"