BigRedNole,
We have plans in the very near future to incorporate a mechanical float valve into the magnet holder where the sensor is currently located. This will provide a secondary backup. This will be an option for $15 and anyone who has purchased the ATO in the past will be eligible for upgrade at the $15 price if they wish to do so. That said, our switch is extremely reliable and meets military specifications for aerospace use, but we do understand the backup mentality, we are reefers too!