I can vouch for the Tunze ATO pump working well in a normal setting. I used it for quite a while.
But I ended up with my "Reef Angel" controller, controlling a peristaltic pump.
I needed that new pump, since my RO water is outside, and the water tube goes across the roof of my garage.
That roof-run required too high of a head pressure on most pumps, including the Tunze.
I got tired of filling a smaller reservoir near the tank.
The nice thing about the reef angel is that I could program in a safety system myself.
I know roughly how much water is needed per day, so it is programmed to
never exceed that by more than 50%, regardless of what the sensor says.
And it comes with an extra sensor, which I may hook up someday.