Jack's Magic Purple Stuff is a great choice when it comes to preventing stain and scale in your pool! It is part of the Green Stuff Program that helps save 200 million gallons of pool water a year from being drained after being acid washed. What makes the Purple Stuff unique, is the fact that is designed to meet the demand that salt chlorine generators and high TDS (total dissolved solids) put on a sequestering agent. It removes metal from the water and helps keep silica in solution, as well as helping to prevent scaling of the cells in the salt chlorine generator. Start Up Dose: Add 1 qt. per 10,000 gallons Maintenance/Prevention: Maintenance levels are 10-12ppm, can be tested with Jack's Magic Sequest Kit. Otherwise, an estimated dose is 6-8 oz. per 10,000 gallons weekly. Contact the pros at PoguePoolSpa.com for more information.