Ok thx. The tub size are 25q, 19x15x7 inches tall. Will be using cocofiber as substrate. I will place the tstat probe under one of the tubs, so it's between flexwatt and tub. Should I tape the flexwatt so I can get it nice and close to the bottom if the tub or will it be ok laying flat? Cuz like I said the tuba aren't perfectly flush flat on the bottom. They kinda go in on the middle