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Pool shocks are crucial chemicals for pool maintenance, helping to prevent bacterial and algae growth while addressing various contaminants. Depending on the size and application method, most pool shocks typically cost between $3 and $7 per pound. Pool shock is generally available in pre-packaged bags or in larger containers like gallons or buckets that require mixing.
To help you find the best pool shock for your needs, I reviewed dozens of options. Overall, my top pick is the HTH 52037 Swimming Pool Care Shock, which works on all swimming pools and can treat up to 13,500 gallons per pound. Check out my full list of the best pool shocks below.
Best Pool Shocks: Our Top 6 Picks
- Best Overall: HTH 52037 Swimming Pool Care Shock
- Best Fast-Acting: DryTec Chlorine Shock Treatment
- Best for Large Pools: In The Swim Pool Shock
- Best Liquid: Austin’s Pool Tech Shock
- Best Water Clarifier: Robarb Super Blue Clarifier
- Best Granular: Clorox Pool & Spa Swimming Pool Shock
Compare Top Pool Shocks
| Product | Quantity | Treatment Amount | Active Ingredients |
|---|---|---|---|
| HTH 52037 Swimming Pool Care Shock | 12 one-pound bags | Treats 13,500 gallons per ounce | Calcium hypochlorite |
| DryTec Chlorine Shock Treatment | 24 one-pound bags | Treats 10,000 gallons per pound | Calcium hypochlorite |
| In The Swim Pool Shock | One 25-pound bucket | Treats 10,000 gallons per pound | Calcium hypochlorite |
| Austin’s Pool Tech Shock | One-gallon jug | Not listed | Sodium hypochlorite |
| Robarb Super Blue Clarifier | 32-ounce bottle | Treats 5,000 gallons per ounce | Not listed |
| Clorox Pool & Spa Swimming Pool Shock | Six one-pound bags | Treats 12,000 gallons per pound | Sodium hypochlorite |
| Product | Quantity | Treatment Amount | Active Ingredients |
Terms To Know for Pool Shock
Calcium hypochlorite vs. Sodium hypochlorite: Calcium hypochlorite is a strong, and fast-dissolving material that’s common in most pool shocks. However, it could be damaging to vinyl sidings. Sodium hypochlorite, meanwhile, is not as strong as calcium and takes a longer time to dissolve, but it typically has a lower price point.
Best Overall
HTH 52037 Swimming Pool Care ShockDEWALT 20V MAX
- $56
Prices taken at time of publishing.
Good for: Homeowners seeking a calcium hypochlorite shock that works in a variety of pool types.
What Are People Saying About the HTH 52037 Swimming Pool Care Shock?
I found that several customers who left positive reviews for this pool shock were pleased with its pre-measured packets that made it easy to add the exact right amount of shock without overstabilization. Others liked its fast-acting formula and excellent value. However, some others found the packaging to be subpar, and others had issues with the shock not fully dissolving at the bottom of the pool.
“… I highly recommend the HTH 52037 Swimming Pool Care Shock Advanced for anyone looking for an affordable and effective pool shock. Its cal hypo formula, combined with the convenience of pre-measured packets, makes it a reliable choice for maintaining a clean and balanced swimming pool. Furthermore, the significant cost savings compared to local pool stores add to its appeal. If you’re seeking a high-quality pool shock that offers exceptional value, look no further than the HTH 52037 Shock Advanced. It definitely deserves a well-deserved five-star rating!” — Trey via Amazon
“Unfortunately, this last order would not dissolve. I have used HTH multiple times and have always been happy. Most of the bag on the last 2 treatments never dissolved, white speckles are sitting at the bottom of the pool. We first thought it was from our sand filter, then realized it was the shock. (I did an experiment where I tried to dissolve the treatment package in a bucket before using, it never fully dissolved.) I’m not sure I will reorder this brand.” — Natalie via Amazon
Best Fast-Acting Pool Shock
DryTec Chlorine Shock Treatment
- $106.99
Prices taken at time of publishing.
Good For: People who regularly host parties or need to quickly shock their pool.
What Are People Saying About DryTec Chlorine Shock Treatment?
Customers praised this pool shock formula, stating it was strong, fast-acting, and long-lasting. However, some customer reviews I read mentioned that they did have to use multiple packages to treat their entire pool.
“I travel frequently, sometimes for extended periods of time, which makes pool maintenance without hiring a service a real pain. This is particularly troublesome with an in-ground pool in Florida in Summer that has no shade. I waited to post a review until after I’d ordered 2 separate batches to test for quality control, and quite simply: this is the BEST shock I’ve ever used. I’ve come back from trips to solid green slime pits with heavy stripes of the dreaded black spot algae, and 2-3 bags of this stuff + a couple of chlorine tablets with the filter running will turn my pool back to blue overnight.” — Eryn Lockhart via Amazon
“Other one-pound shock packets dissolve very quickly when I sprinkle them around the pool with little residue, and within an hour, there remains no trace of any in the pool. This product does not dissolve well, with most of the product hitting the pool floor. It takes several hours for it to dissolve, even if I stir it up off the floor. It will just settle back down.” — David Lloyd via Amazon
Best for Large Pools
In The Swim Pool Shock
- $144.99
- $167.79
- 14% off
Prices taken at time of publishing.
Good for: Homeowners with large pools who are looking for a cal-hypo shock that eliminates contaminants.
What Are People Saying About the In The Swim Pool Shock?
My research showed that customers who gave this product a positive review were impressed with its easy application and fast-acting formula. Others commented on how well it also worked in conjunction with the In The Swim Pool chlorine tablets. On the other hand, there were a few reviewers who felt this pool shock didn’t come well packaged, and others had issues with it not dissolving properly.
“I use this once a month along with the same brand chlorine tabs and my pool looks great! Easy to use and sprinkle throughout the pool and spa area. I let it work for a couple of days during swimming season before getting in it, then backwash after a week. I would recommend using this along with their chlorine tabs.” — Coach via Amazon
“It mentions on the package that ‘if’ the product doesn’t dissolve at first, just stir up the water. We gave it the benefit of the doubt the first few times we dropped this in, but having to stir a dissolvable powder 3-4 times in a 9-foot pool (albeit a very first world problem) is still an inconvenience. Other products we’ve purchased dissolve within minutes but this just sinks straight to the bottom and sits there.” — Stephen Lloyd via Amazon
Best Liquid Pool Shock
Austin’s Pool Tech Shock
- $19.49
- $21.55
- 10% off
Prices taken at time of publishing.
Good For: Someone who wants a ready-to-use formula for a smaller pool or spa.
What Are People Saying About Austin’s Pool Tech Shock?
I found that customers were impressed with how easy this pool shock was to use and how quickly it cleared debris from their pool. Others liked that it was tightly wrapped and did not leak out easily from the jug. On the other hand, some customers had issues with the weakness of the shock, claiming that it required at least a quarter of the bottle to work effectively. Several other customers also felt this product was overpriced for what it provided.
“I wish that I would have found this sooner!!! After spending boatloads of money on different things to get my pool clear, am I ever happy with this product! My pool would not clear up. I poured in about 1/4 of this bottle in my big above-ground pool and in one day, it cleared up! In fact, I’m contemplating getting rid of the chlorine tablets altogether and sticking with this product. Best thing I’ve found on Amazon!” — Bonky via Amazon
“Way too weak to provide any shock value. Fine if you want to use 25% of the bottle every day, but that is clearly uneconomical. Stick with traditional shock and apply weekly.” — Lovemonger1 via Amazon
Best Water Clarifier
Robarb Super Blue Clarifier
- $19.99
Prices taken at time of publishing.
Good For: Pool owners who want to improve the clarity of their pool water.
What Are People Saying About Robarb Super Blue Clarifier?
Those who gave this product positive reviews said that it was able to clean even the dirtiest of pools. They also mentioned it working in pools of various sizes. However, I found that dissatisfied customers thought that the formula was watery and the instructions were difficult to follow.
“My pool was so cloudy, and my dad didn’t want to believe me that this stuff works. So I totally dumped half in mixing it around with the net, and four days later, I dumped the other half, and it’s crystal clear! It was so cloudy and foggy before! Make sure you mix it around in there so it doesn’t just sink to the bottom. I know I didn’t use it as directed, but my pool was so cloudy and dirty, it’s 20,000 gallons so it helped ten fold. 10/10 recommend for reopening your pool and cloudiness.” — katie septelka via Amazon
“One thing the instructions fail to tell you is to dilute in a bucket of pool water before adding to the pool. Most seasoned pool owners know this, but first-time pool owners might not. Just beware, this product can stain your finish if dilution isn’t accomplished. Other than that, it works as advertised, although adding it once a week might be overdoing it depending on pool size.” — brazos2 via Amazon
Best Granular
Clorox Pool & Spa Swimming Pool Shock
- $32.99
Prices taken at time of publishing.
Good for: Pool owners looking for a granular shock in pre-packaged bags.
What Are People Saying About the Clorox Pool & Spa Swimming Pool Shock?
Those who gave this product a positive review liked that it was effective at removing algae and maintaining its chlorine level. Others appreciated how quickly it worked and its simple application. However, some others felt it had misleading packaging and didn’t have as much chlorine in the packets as advertised. Some also were disappointed that this shock increased their pool’s CYA levels.
“I have two small pools, an indoor plunge pool and an outdoor above ground pool I set up in summer. I use both pools for swimming with a swim tether almost every day, and I use this in both pools and in my hot tub as well. It works well for all of them, but it is especially useful in the outdoor pool. If I shock that pool weekly, I never have any problems with algae. Also, I notice that if I keep the pools and hot tub at the recommended chlorine level, they always smell fresh, without any chlorine-y or stale smell.” — KB via Amazon
”Good product, but beware – CYA levels will increase with repeated use of products with Di or Tri chloride (like this shock contains). The more CYA you have the higher your chlorine levels need to be to kill bacteria, etc (meaning spending more on chlorine and shock). Continually using DI and TRI chloride products is fine if you plan to drain pool water and refill (only way to correct high CYA)… This product works but just know what other additives you are adding to your pool.” — Kim via Amazon
What To Know Before Buying Pool Shock
While all pool shocks operate similarly, finding the best option for your situation can depend on several different factors. Before choosing a pool shock, it’s important to understand the types of shock available, as well as their active ingredients. You’ll also want to consider quantity, dissolving speed, and the type of pool you have to find the best product. Read my buying guide below for more information on choosing the best pool shock for your home.
What are the different types of pool shock?
Pool shock comes in liquid, granular, or tablet form and use one of three active ingredients to remove cloudy water:
Calcium Hypochlorite
This is the most common type of pool shock on the market. It’s strong and fast-dissolving, but it can damage vinyl pool linings.
Sodium Dichlor
This pool shock isn’t as strong. It slowly raises your pool’s pH, so you have to wait some time for it to dissolve before you can swim.
Potassium Monopersulfate
This non-chlorine shock removes bacteria and algae by oxidizing the water. You can use it when you don’t want to raise the available chlorine level of your pool.
What amount of pool shock is enough to treat your pool?
Generally speaking, you need about one pound of pool shock per 10,000 gallons of water. Before you purchase pool shock, determine how much comes with the order. Some manufacturers sell pool shocks in bulk to reduce the number of orders you have to place during the swimming season.
How is dissolve speed measured in pool shock?
Pool shock comes in quick-dissolving and slow-dissolving formulas. If you need to use your pool shortly after shocking it, choose a quick-dissolve version.
What pool types work with pool shock?
Most pool shocks are designed for chlorinated indoor or outdoor pools. However, certain types of pools may require specialized pool shock. These types include:
- Fiberglass-lined pools
- Hot tubs and spas
- Saltwater pools
- Vinyl-liner and above-ground pools
Pool Shock Functions
All pool shock treatments will act on organic contaminants and encourage clear water. However, some specialize in certain functions. Common specializations include:
- Algae mitigation
- Bacteria removal and prevention
- Chloramine removal
- Improvement of free chlorine levels
- Balancing of pH levels
- Storm debris breakdown
- Water clarification and tone enhancement
- Winterization prep
Frequently Asked Questions About Pool Shock
Does pool shock contain chlorine?
Pool shock uses calcium hypochlorite, sodium dichlor, or potassium monopersulfate. Of these chemicals, only potassium monopersulfate is chlorine-free.
How often should I put pool shock in my pool?
For ideal pool care, shock your pool once a week during the active swimming season as well as at the beginning and end of the season.
You may wish to shock your pool following heavy rainstorms, as the added water can upset the chlorine balance.
You can also shock your pool if you notice that you have cloudy water or tinted green.
What does it mean if my pool shock is stabilized?
Stabilized pool shock contains a UV protection compound that prevents it from burning in the sun. Any pool shock with sodium dichlor is stabilized.
Our Methodology
This Old House has empowered homeowners and DIY-ers for more than four decades with top-notch home improvement advice in the form of television programs, print media, and digital content. Our team focuses on creating in-depth product and service review content. To date, we’ve published over 1,600 reviews on products in the home space, including power tools, outdoor equipment, major appliances, kitchen gadgets, electronics, and more that focus on product quality and helpfulness to our readers.
To provide our readers with the best recommendations possible, we rely on several key sources of information to help guide our selection process.
Initial Research: Our research process began by generating a list of pool shock with a significant number of verified buyer reviews and an average customer review rating of 4–5 stars. We looked at positive and negative reviews alike, focusing on information from both satisfied and critical buyers.
Expert Insights: To complement our in-house expertise, our team looked at reviews and videos from trusted publications and independent testers, spoke with subject matter experts, and drew insights from reader contributions.
Final Product Selection: We then began fine-tuning our list by replacing older models with the latest versions and eliminating any discontinued models. From there, we compared each model’s feature set to create a final short list, selecting the best-in-class options for various buyers, budgets, and scenarios.
Once we conclude our research, we craft a comprehensive, user-friendly article of recommended products and additional information to help our readers make the right purchase.
Questions or Comments?
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