Thank you. I don't use any particular pre-made system for the water changes. I assembled the components for it.
The drain is via a siphon to the basement. An electric solenoid bought off Amazon (normal off, zero pressure required for operation) is used to turn the siphon flow on/off.
A water level float sensor is used to control the fill. There's also a backup sensor in case the primary fails - wouldn't want a flood. The float sensor is used to control a pump that pumps the water from the container the RO unit puts the water into up to the tank. It's really that simple.
There's an additional pair of float sensors that are used to control turning off/on the filter when the water level in the overflow drops too low.
I got the float sensors from autotopoff.com.
The Digital Aquatics controller is used to tie all of this together. For timing, I just let the siphon go and timed how long it took to drop the water level the amount I wanted it to drop, then programmed the controller to open the solenoid for that period of time.
