Check the listing for details. Poolife Back To Blue 4.6 lb - 6 Pack. Condition: New. Listed at 241.99 USD. If you are experiencing a severe algae bloom, which has turned your pool green, the POOLIFE Back to Blue Shock System can turn your pool sparkling blue again. This two-part system destroys the bacteria and algae that have taken over your pool and then makes it easy to vacuum out. At the start of the season, or if a severe algae bloom occurs during the season, the pool can be treated and returned to its clear blue appearance within 24 hours by using POOLIFE Back to Blue I and POOLIFE Back to Blue II as part of the POOLIFE Back to Blue Shock System. Product Benefits: Good for all pool surfaces Restores water clarity All-in-one chlorinates, shocks, and kills algae Transforms water from green to blue in 24 hours Drops particles and dirt to bottom of pool For use only with systems that allow vacuum to waste Treats pools up to 15,000 gallons