General Operations and Function of Legionella Control Water Softeners Service Cycle Both Legionella control water softeners are online, allowing one worker and one polisher. Softener A is lead and Softener B is lag. Water passes through the lead (A) tank then passes through the lag (B) tank. Softener B is lead and Softener A is lag. Water passes through the lead (B) tank then passes through the lag (A) tank. Softener A Regeneration Softener A is in regeneration Softener B is online with no polisher Softener B Regeneration Softener B is in regeneration Softener A is online with no polisher For more information please visit our Legionella Control Water Softener Systems page or contact us now to learn more about our Water Management Programs and Water Testing so you can focus on your core business operations and let the experts focus on your water treatment needs. Contact Legionella Control Systems for CDC Legionella risk assessment and Legionella testing. Request Proposal Contact Us