About This Item The HTH Super Green to Blue Advanced Shock is a 2 part system. Pack I shocks your pool with a boost of chlorine helping you fend off bacteria. Pack II is a powerful flocculant that drops particles to the bottom of the pool for easy vacuuming. Both packs work together to create beautiful crystal clear pool water within 24 hours. How To Use HTH Green To Blue Advanced Shock System Simply follow the onnpack instructions for both Pack I and Pack II. Pack I is the Cal Hypo Shock treatment and Pack II is a flocculant that drops dead particles to the bottom of the pool for easy vacuuming. About HTH Pool Care HTH was developed with the pool owner in mind. We know that maintaining your pool water can be a lot of work. That is why we are here every step of the way helping you clear the uncertainty from pool care. With economical easy to use solutions HTH is designed to work hard so you are prepared to tackle whatever life throws in your pool. From balancing your water to treating green water, we offer a full line of products to keep your pool water healthy and your swimmers happy.