 Many level one contaminants like your arsenic, nitrates. But it's still considered extremely hard. Then the disinfectants, there is chlorine, some chloramine in the water. Different things, too. And as a water specialist, I come in, I know exactly what we're dealing with in our water. And I have a system that is designed exactly for this, our municipal water. And I have it dialed right in, and I'm very happy with it.