Owning a pool brings enjoyment and relaxation, but proper maintenance is essential to keep it safe, sparkling, and inviting. One crucial aspect of pool care is pool shocking, a process that effectively eliminates bacteria, algae, and contaminants. With various types of pool shock on the market, choosing the right one can feel overwhelming. In this guide, we’ll break down the best pool shocks to meet different needs, helping you make the best choice for your pool.
Contents
What is Pool Shock and Why is it Essential?
Pool shock is a concentrated form of chlorine or non-chlorine oxidizer that kills harmful organisms, sanitizes the water, and restores clarity. Regular pool sanitization methods alone often can’t handle larger contaminant loads, especially after rainstorms, heavy usage, or algae outbreaks. Shocking, also known as superchlorination, introduces a large dose of sanitizer that rebalances the pool’s chemistry and purifies the water quickly.
Pool shocking is recommended weekly for regular maintenance and as needed in cases of cloudy water, visible algae, or a strong chlorine smell. Here’s a closer look at the most popular and effective types of pool shock.
Types of Pool Shock
1. Calcium Hypochlorite (Cal-Hypo) Pool Shock
Calcium hypochlorite is one of the most commonly used types of pool shock due to its high chlorine concentration, typically 65-75%. It’s ideal for killing bacteria and algae and is often available in granular or powdered form.
Benefits:
- High effectiveness: Due to its strong chlorine concentration, it works quickly and can handle tough cases like algae blooms.
- Affordable: Cal-Hypo is one of the most cost-effective pool shocks available, making it an economical choice for routine maintenance.
- Easy to store: It has a long shelf life, which is convenient for seasonal use.
Drawbacks:
- Requires pre-dissolving: Cal-Hypo can leave residues if not dissolved properly before adding to the pool.
- Raises calcium hardness: Overuse can increase calcium levels in your pool, leading to scaling issues, especially in hard water areas.
2. Sodium Dichlor Shock (Dichlor)
Sodium dichlor pool shock, or simply Dichlor, is another effective choice with a chlorine concentration around 55-62%. It dissolves quickly in water and contains stabilizers that protect chlorine from breaking down under UV rays.
Benefits:
- Fast-dissolving: Dichlor dissolves quickly, making it suitable for regular shock treatments without pre-mixing.
- Stabilized with CYA (Cyanuric Acid): It resists UV degradation, so it’s a good choice for outdoor pools exposed to direct sunlight.
- Gentler on surfaces: Compared to Cal-Hypo, Dichlor is less harsh on vinyl and fiberglass pool surfaces.
Drawbacks:
- Increases Cyanuric Acid levels: Over time, Cyanuric Acid can build up in your pool, potentially leading to chlorine lock, where chlorine becomes less effective.
- More expensive: Dichlor is usually more costly than Cal-Hypo, which may be a factor for pools requiring frequent treatments.
3. Potassium Monopersulfate (Non-Chlorine Shock)
Non-chlorine shock, known as Potassium Monopersulfate or MPS, is an excellent alternative for people sensitive to chlorine. MPS oxidizes organic contaminants, removes chloramines (the source of strong chlorine odor), and does not add chlorine to the pool.
Benefits:
- No added chlorine: It’s ideal for saltwater pools or spas where chlorine levels are already sufficient.
- Reduces chloramine build-up: Helps eliminate combined chlorine without impacting free chlorine levels.
- Quick re-entry time: With non-chlorine shock, swimmers can re-enter the pool within 15 minutes.
Drawbacks:
- Less effective against algae and bacteria: MPS is an oxidizer, not a sanitizer, meaning it’s best for routine maintenance rather than handling algae blooms or bacterial outbreaks.
- Higher cost: MPS is generally more expensive than chlorine-based shocks, which may make it less practical for large pools.
4. Lithium Hypochlorite Shock
Lithium Hypochlorite is a lesser-known, chlorine-based shock with a chlorine concentration of around 35%. It dissolves quickly and leaves little to no residue, making it ideal for quick applications.
Benefits:
- Dissolves rapidly: Lithium Hypochlorite is easy to use and doesn’t require pre-dissolving.
- Effective at low temperatures: This shock works well even in cold water, making it useful for off-season maintenance.
- Residue-free: It leaves no residue, making it safe for all pool types, including vinyl and fiberglass
Drawbacks:
- High cost: Lithium Hypochlorite is one of the most expensive types of pool shock, which may be prohibitive for regular use.
- Less available: Due to its price and limited demand, it’s not as commonly stocked as other pool shocks.
Top Pool Shock Products
To help you choose the best pool shock for your needs, here’s a breakdown of some of the top-rated options in each category.
1. HTH Calcium Hypochlorite Pool Shock
- BENEFITS: Stay all clear for cannonballs; This fast-dissolving, convenient 4-in-1 formula kills bacteria and algae, reduces chlorine odor and irritation, and quickly restores crystal clarity
- FEATURES: Multi-functional shock treatment for weekly use to solve 90% of pool water problems within 24 hours and restore crystal clarity
- VISIBLY BRILLIANT SPARKLE: This Cal Hypo based formula sanitizes without adding cyanuric acid (CYA) to prevent overstabilization or chlorine lock
- COMPATIBLE WITH ALL SWIMMING POOLS: This product is great for all pool types including vinyl-lined pools and saltwater systems
- YOU'RE ALL CLEAR WITH HTH: For best results, use with HTH 6-Way Test Strips to test and balance your swimming pool water twice weekly
HTH Super Shock is a popular Calcium Hypochlorite shock with a high chlorine content that makes it ideal for tough algae and bacteria problems. It’s formulated to dissolve quickly and leaves minimal residue.
Best For: Algae outbreaks, cloudy water, and routine weekly maintenance.
Usage Tips: Dissolve HTH Super Shock in a bucket before adding to the pool to avoid bleaching the liner or leaving residue.
2. Clorox Pool & Spa XtraBlue Shock
- Our chlorine free pool shock-oxidizer comes in convenient 1 pound bags
- Other applications and weekly maintenance will not affect other chemical levels.
- Safe enough to swim right after application!
- Use chlorine free pool shock-oxidizer on a weekly basis for best water maintenance.
- Dosage: 1 Pound per 10,000 gallons
Clorox XtraBlue is a Dichlor-based shock that’s stabilized with Cyanuric Acid to prevent UV breakdown. It also includes algae-fighting agents, making it a multi-functional choice.
Best For: Sunny outdoor pools that need regular maintenance without losing chlorine to sunlight.
Usage Tips: Pour directly into the pool for quick dissolution. Avoid overuse to prevent cyanuric acid buildup.
3. In The Swim Chlorine-Free Pool Shock
- Our chlorine free pool shock-oxidizer comes in convenient 1 pound bags
- Other applications and weekly maintenance will not affect other chemical levels.
- Safe enough to swim right after application!
- Use chlorine free pool shock-oxidizer on a weekly basis for best water maintenance.
- Dosage: 1 Pound per 10,000 gallons
In The Swim Chlorine-Free Shock is a popular MPS shock that works well for indoor pools, spas, and saltwater pools where chlorine levels are already managed.
Best For: Routine maintenance in saltwater pools or indoor pools with sensitive water chemistry.
Usage Tips: Add directly to the pool and wait 15 minutes for re-entry. This shock is ideal for pre-party treatments to freshen the water without a chlorine spike.
4. Leslie’s Power Powder Plus
- Fast Acting Pool Shock Treatment: Quickly boost the chlorine levels in your pool to remove algae and other contaminants for crystal clear pool water
- Pro-Grade Cal Hypo Pool Shock for Regular Maintenance: Made of 68% calcium hypochlorite, with 65% available chlorine, regular doses of this chlorine shock treatment keep your pool clear all season long
- Easy to Use: Each pound of chlorine shock comes in its own easy-to-use bag for quick, measure-free use
- How to Use: Use one 1lb bag of Super Shock per 10,000 gallons of water. Spring openings and pools that have extensive algae blooms may require 2-3 doses to properly treat and sanitize
- Made in the USA: Doheny's Super Shock is manufactured and packaged in the USA
Leslie’s Power Powder Plus is a high-potency Cal-Hypo shock with 73% available chlorine. It’s effective against green, black, and mustard algae and works quickly, making it a favorite among pool owners.
Best For: Heavy-duty cleaning after storms, heavy use, or for handling severe algae problems.
Usage Tips: Pre-dissolve in a bucket, then pour around the pool edges to prevent liner bleaching.
How to Shock Your Pool: Step-by-Step Guide
- Test Pool Water: Always check pH, alkalinity, and chlorine levels before shocking. The ideal pH for shocking is between 7.2 and 7.4 to maximize chlorine effectiveness.
- Select the Right Shock Type: Choose based on your specific pool needs, water type, and recent usage. For regular maintenance, calcium hypochlorite or dichlor shocks are generally effective, while non-chlorine options are excellent for maintenance with frequent swimmers.
- Pre-dissolve if Necessary: If using Cal-Hypo or any shock that needs dissolving, mix it in a bucket of water to prevent residue and distribute it evenly.
- Shock at Night or Evening: For chlorine-based shocks, apply at dusk or evening to prevent chlorine loss from sunlight.
- Distribute Evenly: Pour the shock mixture around the pool edges or in front of the return jets to circulate it effectively.
- Wait Before Re-entry: Observe the recommended wait time, typically 15 minutes to several hours depending on the type of shock and pool volume.
Pool Shock Frequency and Tips
Regularly shocking your pool is key to maintaining clear, clean water. For most pools, weekly shock treatments are effective, but increase frequency after heavy usage, rainstorms, or visible algae. For seasonal pools, a final shock before closing will prevent algae growth during winter.
- Avoid Over-shocking: While shocking is crucial, too much can harm your pool liner and surfaces. Follow manufacturer guidelines for the right dosage.
- Wear Protective Gear: Pool shock chemicals are strong. Wear gloves and goggles when handling them.
- Store Safely: Keep pool shock in a cool, dry area, away from other chemicals, to prevent dangerous reactions.
Conclusion
Using the best pool shock for your pool is essential to keep the water clean, clear, and safe for swimming. Choose from options like Calcium Hypochlorite, Dichlor, Potassium Monopersulfate, or Lithium Hypochlorite, each with its own benefits tailored to specific needs. Regular pool shocking, proper testing, and using quality products can make a significant difference in your pool’s appearance and health. Let’s keep your pool in pristine condition all season long with the right shock treatment!
