WELL-X-TROL Well Tank w Durabase Stand WELL-X-TROL redefined the industry in 1963 as the first pre-pressurized diaphragm well tank. With its sealed air charge and unique water chamber design, Well-X-Trol remains the choice of professionals. The butyl diaphragm in all models meets EPA requirements for potable water as defined in the Safe Drinking Water Act of 1986. The entire tank which includes the virgin polypropylene liner, butyl diaphragm, and acceptance fittings for a 100% corrosion resistant water reservoir is listed by NSF International Standard 61. Exclusive butyl diaphragm, along with the 100% corrosion-proof virgin polypropylene liner, are secured by a positive hoop ring seal for added strength and reliability. This totally integrated system outperforms other types of water chamber designs. The plated steel air valve is welded rather than threaded to prevent loss of air pressure. The finest quality, custom mill steel is used in the deep drawn dome for extra strength while keeping tank weight to a minimum. Features High-strength steel shell Virgin polypropylene inner liner will not crack, chip, flake or peel Thick butyl rubber diaphragm offers the lowest permeability of any material used today and will not support bacterial growth Heavy duty butyl diaphragm is the thickest in the industry and features seamless construction for uniform strength and flexibility. It conforms exactly to the shell configuration without stretching, creasing, or forming bubbles or corners that could trap water or sediment. Butyl is the best known elastomer to prevent air loss. Diaphragm design will not collapse or tear like bladder designs Stainless-steel system connection withstands aggressive water Welded air valve is permanently attached rather than mechanically threaded to prevent loss of air pressure and to minimize stress on the well's pump system. It also carries a tamper-evident warning label. Deep-drawn steel domes offer twice the strength of rolled steel while minimizing weight. Unique positive hoop ring seal secures diaphragm and liner for added strength and reliability. Polypropylene liner provides a 100% corrosion resistant, non-metallic rigid water reservoir that is listed by NSF International Standard 61. Exclusive welding process eliminates interior rough spots and sharp edges that can damage the diaphragm and liner. Each finished tank is pressure tested for safety. Each finished tank is pre-pressurized to the most common pump cut-in pressure. Exterior appliance-like finish looks attractive while protecting the tank from the elements.