this might be right up you ally then.... it's a voltage controller, with built in Temperature protection.... now normally the thermistor would go onto the block that cools down the Mosfets.... the comparitor then senses the temperature and if for some unplanned reason the temperature goes higher that a preset value (little pot) the TEC's will get shut down, now if you where to relocate that thermistor to your reservoir, you would now be able to maintain a preset temperature just as easily......
