HTH Pool Shock Ultra Calcium Hypochlorite 6-Pack (6 x 1 lb) — Fast-Dissolving, No CYA, Blue Action Indicator

HTH 52040B Shock Ultra is a fast-dissolving, calcium hypochlorite pool shock sold in a 6-pack of 1 lb containers designed to rapidly raise free chlorine and restore clear water.

Use this Cal Hypo-based shock to quickly sanitize swimming pool water without adding cyanuric acid (CYA). The formula is created to tackle bacteria, algae, stains and cloudiness while being compatible with vinyl-lined pools and saltwater systems. A visible blue indicator shows the product in action, and routine use alongside testing helps maintain balanced water and improved filtration performance.

How does this shock restore cloudy or green pool water?

The concentrated calcium hypochlorite delivers a strong dose of free chlorine to oxidize contaminants and reduce organic load that causes cloudiness and algae. It works faster than routine sanitizers to bring chlorine to effective levels, helping filters and clarifiers perform better.

• Adds free chlorine quickly to oxidize organics and algae.
• Blue action indicator confirms dissolution and mixing.
• No CYA added, avoiding overstabilization that can trap chlorine.
• One-week weekly shock can solve most common pool clarity issues within 24 hours.

Is HTH Shock Ultra safe for my pool type and equipment?

This Cal Hypo shock is formulated to be compatible with most pool finishes and systems, including vinyl liners and saltwater pools. As with any oxidizer, follow label dosing, pre-dissolve or broadcast per instructions, and ensure proper calcium and pH balance to protect surfaces and equipment.

• Suitable for vinyl-lined, plaster, and fiberglass pools.
• Safe for saltwater systems when used per directions.
• Monitor calcium hardness and pH to avoid scale or corrosion.
• Use with regular testing (HTH 6-Way Test Strips recommended).

How do I use this 6-pack most effectively and safely?

Handle one-pound containers individually to measure dose and avoid moisture exposure in storage. For shock treatments, apply to circulating water as directed—either pre-dissolved or broadcast according to your pool size—and retest chlorine and pH after treatment before swimming.

• Wear gloves and avoid inhalation when handling granules.
• Follow label dosing for pool volume and condition.
• Allow adequate circulation and wait for free chlorine to return to safe levels before swimming.
• Store unopened packs in a cool, dry place away from other chemicals.

What results should I expect and how often should I shock?

Regular weekly shocking helps prevent algae and maintains clarity; heavy contamination may need treatment more frequently. Many common pool problems clear within 24 hours when shocked properly, but consistent testing and maintenance keep results steady.

• Weekly use addresses about 90% of common pool issues.
• Expect visible improvement in clarity within a day for typical issues.
• Use test strips twice weekly to track free chlorine and pH.
• Increase frequency after heavy use, storms, or algae outbreaks.

Who is this for: HTH 52040B Shock Ultra is aimed at homeowners, pool service pros, and rental property managers who need a reliable, fast-acting calcium hypochlorite shock that doesn’t add stabilizer. It suits anyone maintaining vinyl-lined or saltwater pools who wants a visible action indicator, convenient one-pound dosing, and a multi-pack supply for routine shock treatments.