Hey Pool Owners! Are you adding shock to your pool at the wrong time? If you add shock during the day, it’s a complete waste of chemicals. That’s because most chlorine shock, like cal-hypo shock, is unstabilized. And the sun’s UV rays will break down unstabilized chlorine before it can get to work in your water. So add shock at night with your pump and filter running. Follow us at Swim University for more pool care tips throughout the year. #pool #poolcare #poolmaintenance #poolchemistry #swimun