ATO failure

[gregzz4]

I hate wet floors!
Although I mostly trust my Tunze 3155, I have it plugged into my controller and a float switch in the return section. This will only allow 2 gallons to flow IF the ATO controller sticks 'on'.
The ATO has access to a max of 9g, which in my 115g system would drop my DT from 1.026 to only 1.024. And my sump could handle it all; unless the return pump were to then stop!!

[smokinreefer]

Redundancy and fool proof failsafes are the only way to avoid disaster.

The limiting the amount of water in the reservoir is the safest.

Electronic ato can always fail. Nature of the beast.

Gravity fed can also fail... Something gets stuck on the float, etc.

I've had issues with both methods.

I've only had a near hobby ending experience with my gravity fed. (Mind you it was with a large reservoir going through a kalk reactor)