Check the listing for details. Leisure Time Spa Scale Control Spa Defender 1 qt (B). Condition: New. Listed at 29.99 USD. Especially designed to prevent scale formation in spas and hot tubs. Weekly:1. Add directly to spa. Use 2 oz. for spas up to 800 gallons. Use 4 oz. for spas over 800 gallons.2. Run filtration system for one hour, or normal filter cycle. Tips: Control of calcium can be very challenging, especially in spas. Regular use of Defender will prevent mineral buildup from occurring and causing the spa's heater or equipment to fail. Use as a follow-up to Metal Gon, applied at start-up. Compatible With: Chlorine, bromine, ozone and biguanide sanitizers. Advantage: Use as part of the Simple Spa Care Program Powered by Frooition Frooition | No-js Template | eBay design, eBay store design, eBay shop design, eBay template design, eBay listing design (ver:froo_no_js) This listing is currently undergoing maintenance, we apologise for any inconvenience caused.