Water goes through a reverse osmosis membrane very slowly and people don't have the patience to wait a long time to get a cup of water. For this reason the residential RO units need a water storage tank to store the purified water. The RO tanks can delivery stable and constant water flow when the faucet is opened. The concern that pollutants might come from air or animals with the use an opened tank favors the use of a closed expansion tank.
Brass and copper are banned for use in purified/drinking water since they are prone to leach lead. All our expansion tanks use stainless steel connections to avoid the lead leaching concerns.
Our tanks are NSF approved under standard 58.
FEATURES:
Food Grade Diaphragm Imparts no Foul Tastes or Odors to Water