HTH™ Pool Care Green to Blue Advanced Shock is a 2 step green to blue pool recovery system designed to correct severe green water caused by algae blooms. 

• Advanced I delivers a powerful calcium hypochlorite (cal hypo) shock that kills algae and bacteria without adding cyanuric acid (CYA), helping avoid chlorine lock.
• Advanced II is a pool flocculant that binds to dead algae and fine debris, causing it to sink to the pool floor for direct vacuuming to waste. 
• Used together and with the proper pool equipment, this system can turn pool from green to blue in as little as 24 hours. 
• It is safe for vinyl‑lined pools when used as directed and is especially effective after storms, heavy algae outbreaks, or periods of high pool use.

You're All Clear with HTH™!