My overhead heat bulbs do not seem to keep the terrarium quite hot enough for my BP (high 70s-80F). I wanted to go with an under-the-tank heater solution; however, while the bottom of my tank is glass, there is plastic covering the underside of it (the side facing the shelf). Most UTHs advise not to place them on plastic, as melting is an obvious concern. I was thinking of getting something to put under the substrate (cypress mulch), but wasn't sure what options there might be for this. I could also place a UTH on the side of the tank, but I've heard it is usually better to heat from under the snake, as they are accustomed to belly heating. Any advice? Thank you!