Typically, you close your pool in the fall with a dose of Pool Magic. The enzymes control the organics that seep into the water during the off season and minimize the work to re-open or start the pool up. However, if you didn't use Pool Magic in the fall, you will still benefit by adding it during opening. Pool Magic contains SMARTZyme technology. SMARTZyme technology wastes no time breaking down organic materials. A small amount of Natural Chemistry's enzymes can treat large amounts of water due to their ability to bind to organic contaminants and reduce them to smaller and smaller parts, breaking them down to their original components such as carbon dioxide and water.