what size uth? And using it on a tub?

[brillobee]

I have a plastic tub, 18x10 floor space, about 13 gallons. Which uth should I use the one for 10-20 gal looks too small and 30-40 gal one looks too big. I'm planning on sticking it right on the bottom of the tub, and controling it with a dimmer, will that be ok? The warning on the uth says for glass tanks only.

 

[scm133]

Look at Bean Farm. I think that is where I got mine for the plastic roach bin. The zoo med ones are just for glass. The mat should take up 1/3 floor space of your bin.