Call for availability40Gallon Storage/ Retention Tank. $495 *80 Gallon Storage/Retention Tank. $688 *120 Gallon Storage/Retention Tank. $779 Accelerator In-line Mixer/Booster. $99 When you need "contact time"(time for the water to stay in a tank with chlorine or other chemicals to do their job) these tanks are the way to go. These lightweight tanks have no metal to corrode and offer an opportunity to "drain off" excess iron, sediment and other unwanted contaminant safter they are collected to keep them from ever entering your water supply in the home. NOTE: Optional "Accelerator"($99) makes a small tank act like a much bigger tank for people who have available space problems. NOTE: You MUST have sample ports before and after retention tanks in order to test chlorine levels. ALSO NOTE: * 80,120 gallon tank not available for shipping by UPS Ground. It comes as "freight only" which means it is delivered by semi-truck. Read about the unnecessary usage of Retention Tanks. For more well water treatment information try this:Water Filters of America™® Chemical Feed, Chlorine Injection