Prodibio Iodi Plus - Saltwater Avail in Nano Range: 1 vial per product up to 15 gal/15 days; Standard Range: 1 vial per up to 50 gal/15 days; Pro Range: 1 vial up to 500 gal/15 days Long shelf life thanks to single-dose glass vials being packed with argon gas to eliminate oxygen; Bacterial products lie dormant until ready Glass vials are tinted; Active ingredients are protected against UV exposure, Concentrated formulas are highly effective and economic Does not require refrigeration; Simply store at room temperature This box contains 30 standard vials of Iodine, Each vial treats 30-50 gal and should be dosed every 2 weeks or as needed, This box treats a total of 900 to 1500 gal