Something i am using now that i kind of stumbled upon which seems to be working great is this:
http://www.grainger.com/Grainger/DAYTON-Float-Switch-1APP4?Pid=search">http://www.grainger.com/Grainger/DAYTON-Float-Switch-1APP4?Pid=search</a>
Its main use seems to be for pulling water out of a sump because when installed right side up as the water rises to the first float it kicked on the pump, once i saw this i realized that i had something that was for the opposite of what i needed. Then my engineering brain kicked in and realized that if i flipped the dual float mechanism upside down it would do just the opposite. So while the sump is full the vertical chamber with the dual floats both stay afloat and the switch stays off, however, when the level drops the first float drops and the switch kicks on until the float gets back up floating again. It then has a feature that you can make it run for 5-30 secs after the float reaches its limit. I love this thing because the floats are protected in a cage like assembly, keeping critters out of it. I also have it on the return portion of my sump so not much gets in there anyways.
I guess its a good a system as any so I don't know why i need an ATO system. I just felt like i needed to look into a system that is made for that purpose. This set up is made for just the opposite but if it works it works. It has a battery you can install that keeps power to the system in the instance you lose power and it has a feature that sets off an alarm if the power to the pump stays energized for longer than a specified amount of time. Almost like it knows that the pump should only run for a certain amount of time and if it runs longer then something is wrong. This saved me the other day because the water line came loose from my sump and fell out of it and this thing started pumping water in once the float dropped. Once it had gone so long it started alarming this loud obnoxious alarm and I came running to find the ATO water line had fallen out and was pumping on the ground.
Anyways I guess I should be happy with this system because i think this is how ATO systems work anyways. Let me know your thoughts or if anyone else is using this thing. It seems to be price comparable to some of your nice ATO systems, maybe even a little cheaper. I got a discount cause i ordered it through my work.
Dale