Use this concentrate with the Porta Stream II and III or the Porta stream I for 5-7 gallons. Creates a buffered , saline solution when mixed with clean, potable water. Replace solution no longer than six months after mixing. One bottle of Fend-All water preservative will preserve 14-16 gallons. Mix with clean, potable water. product has a 30-month shelf life. Sold with tamper evident seals.