I'm posting this to help anyone in the future searching this issue. I have the Hydros ATO kit, and it was simple to set up-- but for the life of me I couldn't get the included water-level sensor to realize it was dry. After speaking with Hydros tech support, it turns out I'd labeled the sensor an "Optical Sensor," which made sense to me (no pun intended)-- but I needed to classify it as a "Triple Optical Sensor," which is another option on the pop-up list. Works fine now.
