Thermostat probe securing...

http://www.neur0.net/setup.jpg
^^ the pic above, the tank on top registers 4 degree difference, its hotter... i didn't think heat actually rose... like that atleast.

I am trying to test every position to put the thermostat probe, but securing it on bottom so its actually physically touching the heatpad, i find almost impossible... What kind of tape can I use for the under side of tank? (it won't be touching the heat pad)

but are there ways I can make it stay, even if it touches the heat....


thanks!

Aluminum duct tape, not just regular duct tape, but aluminum duct tape,,,, it works great and you can get it at Lowes or Home Depot