Aqua Medic added an auto-top off unit to their product line, aptly called the Refill-System. The top off unit features an infrared optical sensor with delayed circuit, as well as a backup float sensor. Aqua Medic mentioned there’s also a safety shutdown circuit in case the level sensor becomes defective. There is a warning system if the refill tank runs low. If the refill pump runs dry, there’s a acoustic and optical alarm to make the user aware. The whole thing runs on a low-voltage 12VDC transformer.
The Refill-System looks well designed and reliable. The mounting hardware for the float switches and controller make for easy installation.