I was thinking just running x amount of time based on how much water was needed, but i feel like this would need to be calibrated often if a filter was dirty or if a pump impeller was wearing ETC. I guess maybe i could use a flow sensor on each inlet to alert when flow is under a certain number, then i could inspect the equipment. If i use a reversible pump, will a flow meter work in reverse as well, or is the reading going to be off if water is going backwards through the sensor?(I'm assuming they flow sensor is directional, unless they make a bi directional flow sensor?)