ATO for system without a sump

So, random question.

I was thinking about building an ATO for my tanks without a sump. Because these tanks are higher off the ground, I don't think that I can employ any sort of gravity fed system, so I'll need to use a pump to pump the water from a holding container through small tubing to the tank.

Now, the best idea I've come up with is to use a 3 check valve system to control the flow of water.

Here's how I'm envisioning it works:
Each tank will have 2 float valves that run in a parallel (i think?) circuit. Both will have to be down, completing the circuit for the pump to kick on. I also want to have a 3rd float switch somewhat higher than the other 2 in the parallel circuit. This will break the circuit if it rises to prevent the pumps from running if, for some reason, both float valves working in parallel get stuck in the "on" position.

Because water will be pumped from a container rather than directly from my RO system, I shouldn't have to worry about TDS creep with this system. I was also contemplating running a timer on the power source to only kick on around 4 times a day. I think this should be sufficient to prevent disaster.

Does this sound like a somewhat do-able setup?

The biggest hurdles I have at this point are:
1) I don't know anything about electricity, but I'm fairly capable so I'm not too worried about figuring it out. But any advice here is greatly appreciated, especially in regards to materials to use.
2) I'm not sure what sort of parts are best to accomplish this, can someone provide some links to get me started in the right place? or suggest products you've used in the past?
3)Is there Anything I can add to my container that will prevent the pumps from running if, say, I forget to fill them up for an extended period of time?

Let's discuss.

 

An ATO in a tank is hard to conceive only because the water level in the display tank is constant otherwise what type of filtration can you possibly have? I have an ATO in my sump because that's where the evaporation occurs. If your not using a filtration system inhabitants will have a rough time staying alive. Can you give me more specifics? Ever go to the Barrier Reef in Boca?

 

For the pump I would use a tom's aqua lifter pumps. They pump around 3 gph, do not back-siphon, and can run dry. The main issue I see is in the DT a small change in level is going to represent more evaporation because of the dimensions. With a sump the return chamber (where evaporation takes affect) is relatively small compared to the rest of the tank.

I have mine set up as kind of a semi-auto top off. I have a tom's aqua lifter pump set up on a switch mounted on the side of the stand. At least once a day I flip the switch and pump and fill the tank up. I have the water pumped into my HOB power filter so it mixes in there before entering the tank.

If you don't have a sump the evaporation occurs in the DT, and it is not a constant water level. Power filters and most HOB skimmers don't require constant water level to function, although it would be beneficial.

 

Thanks for the tip on the aqualifter pumps. Even the switch idea would make my life easier, as I'm currently operating with a funnel and gallon jug of water.

The filter is a canister filter fluval 305. I also have a small in tank skimmer on it, but due to fluctuating water levels, it's acting as more of an air stone than a skimmer at this point.

Also yes, I do go to barrier Reef in boca from time to time. They normally have a good selection of stuff.