UTH placement for a Tub?

I'm trying to get my new tub setup and i'm not sure where to put the UTH. It says not to stick it to plastic so should I just rest it on a piece of tile and space the tub above the heater?

I have mine spaced above the UTH, but now it's actually touching it with no issues. Someone with more experience may be able to back me here. As long as you use a THERMOSTAT there should be no problems. Most UTH will only get to between 95 and 110 degrees, that's not enough to melt the plastic tub. Good luck!

I figured as much, I have it spaced on top of a piece of tile and it seems fine, thanks for the response!

you should be able to get some 1ft square, 1/4" thick polystyrene from most pet stores which would be a good insulator, adequate spacer and porus enough to let heat through without the UTH working overtime.