 Cubic foot of filtration media determines how many gallons of water the system can filter before it has to go through its own cleaning cycle. So water softeners, what water softeners do, they have the ability to clean themselves. So you program it with smart computer technology, you program a water softener to your water hardness needs, and then the system learns your water usage for the first 90 days. And at that point, that becomes a template. It records water usage. It'll tell how much water you're using.