As the current moves, it produces metal ions from the copper and silver. Because water is flowing through the chamber, many of these ions are swept away before they can reach the other side of the electrode. The amount of mineral ions released is controlled by a rheostat, an adjustable transformer that changes 110 or 220 AC current from the power service to low-voltage DC current. The higher the charge, the more ions are released. The polarity switches back and forth between the electrodes' two elements to prevent plating of the cathode - a process that reduces the electrodes' active surface over time.
Every purifier includes a test kit that can measure a precise amount of copper ions in the water.
A single test should be done once a week in the hot summer months. The test only takes a couple of minutes. After the tablet is added to the water sample, you compare the color to a chart on the test kit to determine the copper ion level. This test is called a Chlorimetic Test. The recommended range is between .20 and .30 ppm.