The HTH Super Shock Treatment is the perfect solution to stay all clear for cannonballs. This fast-dissolving, convenient 4-in-1 formula kills bacteria algae, reduces chlorine odor and irritation, and quickly restores crystal clarity. It's a multi-functional shock treatment for weekly use, solving 90% of pool water problems within 24 hours. This Cal Hypo based formula sanitizes without adding cyanuric acid (CYA) to prevent overstabilization or chlorine lock, and is compatible with all swimming pools, including vinyl-lined pools and saltwater systems. For best results, use with HTH 6-Way Test Strips to test and balance your swimming pool water twice weekly, and trust HTH to keep your pool water sparkling clear.