Fleck 2510 - 12 Day Timer Auto Regenerating Tannin Unit 2.5

(If you have a bypass already in your plumbing, then a yoke provides a direct connection. If you don't have a bypass, then select the appropriate size of either the Noryl Yoke with Noryl Bypass or Stainless Bypass. The Noryl Yoke and the Noryl Yoke with Noryl Bypass provide a male pipe thread connection while the Stainless Yoke and Stainless Bypass provide female connection ):

(Select to upgrade control valve to a Fleck 2510SXT.):