heating question?!?!?

I have had my two ball in one 55 gal tank for a couple months now and wanted to get them seperated. So this past weekend I picked up a 32q rack with 5 tubs and a ranco thermostat. I have them all settled in but i am haveing one problem. I have the thermostat set to 94F and the temp in the middle tubs (where i have the probe) wont get above 86F. i assumed that it would heat more to get to my set point. Is it safe to assume NOW that with setting it for 94 means i am only making the Heating element get to that range and not the temp inside the tubs? i hoping im not confusing anyone because I often confuse myself! lol Thank for any help you can provide!

As long as your thermostat probe is directly on the heat tape outside of the tub, then you can crank up the thermostat until the temp on the hot side in the tub is 90-92*F.

The thermostat will almost always be set to a higher temperature than what the actual temp is in the tub.

This is even so with the proportional t-stats aswell.