Swimming pool ionizers discharge metal ions killing harmful bacteria in a pool's water. Pool ions are the most environmentally friendly way to clean a pool. While ionization systems reduce the amount of chemicals needed in your pools, some chemicals are still needed to keep the pool properly sanitized. Compared to other swimming pool chemicals, using pool ionizers will result in less cases of red eyes, dry skin and harsh odors. On average pool ionizers need to be replaced after one year. Pool ionization systems cost more than chlorine or bromine at $200 online, however the reduction in pool chemical costs will save you more overall.