hi! i am using a tub as well and i had the same problem as you. when you say temperature, you mean the hottest point your snake could touch, right? 90 should be what the temperature is UNDER the substrate, not above the substrate or the ambient temperature. to measure this your best bet is an infrared temperature gun, you can get on on amazon pretty cheap.
i put a heat pad (connected to a thermostat) on my hot side, but my cold side was still too cold. to fix this i had to get another heat pad and another thermostat for the cold side, and set it lower than the hot side. i live in a state where it can get very cold, so this may not be necessary for you.
and yes, using a larger tub is fine as long as you fill it up with extra stuff such as fake plants in order to make your snake more secure. test it out, and if your snake is stressed out or not eating that is when i would get a smaller tub.
hope this helps!!
Reply With Quote