Free chlorine residual - the active chlorine level in the pool water after the chlorine demand is satisfied. Ionizer- introduces copper ions into the water to aid in killing algae and bacteria. A chlorine residual must still be maintained and shock treatments are still required. These compounds do not contain chlorine and do not kill algae or bacteria. Ozonator - introduces ozone into the water.
Ozone is a strong oxidizer that helps control algae and bacteria.
A chlorine residual must still be maintained and shock treatments are still required, but they can help reduce the amount of chlorine you must add to your pool or spa to maintain the required residual. Lowers the pH and alkalinity of water. Add directly to pool with pump in operation. Allow pool to recirculate 2-3 hours, retest pH and repeat treatment as necessary. PPM - parts per million, a standard measure of chemical or mineral concentration in swimming pool water.