Why Do We Shock A Pool
Well, its like hitting a giant reset button. Pool shock destroys the algae and bacteria living in your pool and removes combined Chlorine molecules called chloramines.
When you are buying Pool Shock, look for the shock that contains at least 65 to 70% Calcium hypochlorite.
Theres also a non-chlorine shock that only helps to remove chloramines that will not raise the free chlorine level in your pool.
There Was A Surge In Pool Use
People love a good pool party. Your pool, on the other hand, not so much.
Pools should be shocked after heavy usage. This is because people are gross and bring a lot of nasty things into the water.
Seriously though, people introduce a ton of organic pollutants into a pool oils from your skin, sweat, hair, sunscreen, and lets not forget about the dreaded urine and fecal offenders.
With an uptick of swimmers in the pool, the chlorine has to work extra hard to keep it all clean, resulting in a more rapid depletion and consumption.
Shocking For Algae Removal
Its a generally accepted notion that 30 ppm of chlorine residual will kill all algae. Assuming that your pool is clean, and you have adjusted the pH, you can now add the granular chlorine to the pool.
Most pool shock packages will list directions to add 1 lb. of shock per 10,000 gallons of pool water. That may be fine for normal conditions, but if you have a severe algae attack, a triple shock is needed. 1 bag will get reach 7-9 ppm, but for 30 ppm, you need 3, 4 or sometimes even 5+ lbs per 10,000 gallons of pool water.
Shock it until the water turns Blue-ish, said Davy Merino, our blog editor. Thats what I do. A fine technique you do want to add shock to the pool until the water loses the green color, and turns a blue-ish gray color.
Heres a chart that can be used with our Pool Shock and Super Pool Shock products. The numbers indicate the amount of shock, in pounds. You may need more to see the blue color begin to return to the pool.
How much shock is needed to achieve 30 ppm will vary depending on the available chlorine percentage of the shock you are using. For example, if using In The Swim Super Shock, its a 73% cal hypo shock, but HTH Shock -N-Swim is only 45% cal hypo so youd use more or less, depending on the shock potency.
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Most Common Pool Shock Substances
Calcium Hypochlorite is the most common chemical pool shock used to disinfect both residential and commercial swimming pools. This shock treatment kills algae and bacteria that begin to grow in your pool. Most cal-hypo pool treatments contain 65% or more chlorine.
Some brands instruct users to dissolve the substance before adding it to their pool while others explicitly state not to. It is best to follow the instructions on the label of the pool shock treatment you are using.
This shock treatment must be used after dusk. The problem with using it during the day is due to the sun. The heat from the sun will burn the chemical substance before it can do its job. Although this will show lower chemical levels faster, it wont be because of the chemicals doing their job to kill bacteria and algae. Instead, it will be because the sun burned it.
Each pool shock substance has its own time estimation for safety. Its always best to use a test strip to ensure the pools chlorine level is safe before entering. The average time before safely entering the pool is 8 hours. Shocking your pool before bed will commonly allow you to safely swim again the next morning.
Pool Shock Quick Answers
Youve likely heard of the term everything in moderation at some point in your life. Surprisingly, when it comes to shocking your pool, this rule of thumb can be safely set aside. Generally speaking, the answer to Can you over shock a pool? is no, you cannot. You can, however, use more shock than you need or less than is sufficient.
In other words, while you shouldnt worry too much about adding a little extra pool shock, there is still a right way and a wrong way to shock your pool if you want to get the best results. In this quick guide, well review the main factors to consider when carrying out this critical pool maintenance process.
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Testing Pool Water For Chloramines
GOOD: The Aquachek 7 Way Test Strips are easy to use and will quickly give you a free and total chlorine reading. Subtract Free from Total, and you have Combined chlorine level.
BETTER: The Taylor Troubleshooter Test Kit is a liquid DPD reagent kit that also tests for pH, acid demand and alkalinity. Its the perfect pool test kit and is more accurate, and its easier to determine the small differences between Free and Total chlorine levels.
BEST: The SafeDip Digital Tester will not only test for free chlorine digitally but also tests the ORP , a better way to measure active sanitizer levels and most accurately know when to shock the pool.
Not Leveraging The Calcium Hardness In Your Pool Water
As with pH, balancing your waters calcium hardness is essential to a clear, clean, and safe swimming pool. And while you dont want too much because itll cloud the water, a little hardness is actually a good thing.
It helps extend the lifespan of things like vinyl liners, concrete, plaster, fiberglass, and filters.
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Which Is The Best Chlorine Shock Sodium Hypochlorite Vs Calcium Hypochlorite
There are two common types of chlorine shockssodium hypochlorite and calcium hypochlorite and each is used for a different purpose. Apart from these two, there are also other types of special pool shocks including:
- potassium peroxymonosulphate
- lithium hypochlorite
- dichloroisocyanuric acid
However, all these special shocks, including calcium hypochlorite, are not recommended for regular pool sanitization. This is because their continued use introduces other compounds in your pool water, including calcium, pH, and cyanuric acid, leading to increased levels of these chemicals in your water.
This article is mainly about two common shocks: sodium hypochlorite for daily chlorination and calcium hypochlorite for fighting algae during algae breakout.
The type of pool shock to use in your pool will depend on what you need to achieve, which may include clearing cloudy water, killing germs/bacteria, or fighting pool algae.
What Time Of Day Should You Shock Your Pool
The best time of day to shock a pool is in the evening after the sun is down. This allows the pool chlorine time to spread out in the water and clean it before day-time temperatures reduce the effectiveness of the shock. Ultraviolet light reduces the effectiveness of chlorine.
Shocking the pool in the evening also allows you the opportunity to run the pool pump overnight to help distribute the shock around the pool and also this means that the pool will probably be safe to swim after shocking again the following day.
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How Often Do You Shock Your Pool
There are no strict rules on how often you should shock your pool, as it largely depends on the usage and other things like weather conditions. However, most experienced pool owners and experts agree that you need to shock your pool at least once a week or biweekly.
Remember that you are constantly adding more chlorine to the pool water to keep it sanitized, and so it is only a matter of days before chloramines start forming, and you need to shock. That said, for pools that face heavy usage such as those in commercial establishments, shocking might be necessary every few days.
The sanitation system you use also does not affect the frequency of shocking. For example, if you have a saltwater system, you will still need to shock it every other week or even weekly.
Besides the weekly or biweekly pool shocking, it is also important to shock your pool at the beginning and the end of every swimming season. However, before doing it, you should first measure the chlorine levels. Test strips like the JNW Direct Pool and Spa Test Strips will be handy for this.
What Are The Different Types Of Pool Shock
With different pool shocks or shock products are available, how do you know which one is best for your pool?
Heres a breakdown of the top 3 pool shocks.
- Calcium Hypochlorite: Commonly referred to as cal-hypo, this shock is the most popular option, and contains 70% chlorine for killing algae and contaminants. Its unstabilized nature means the sun will burn it off and it wont increase cyanuric acid levels in your pool.
Cal-hypo has a high pH and will temporarily raise those levels, so its a good choice for pools that test at a normal or low pH level. Of note, your water may become temporarily cloudy, and cal-hypo may also increase your waters calcium hardness.
- Dichlor: Sodium dichlor is 55% chlorine and stabilized, which means it contains CYA. This makes it last longer in your pool water than cal-hypo, and the lower pH level and lack of calcium will keep the pool from getting cloudy.
However, because it contains CYA, CYA levels can increase. This has to be carefully monitored otherwise you may need to invest in a CYA reducer, or even drain/dilute your pool.
- Non-Chlorine Shock: Also known as Potassium Monopersulfate , this is a chlorine-free shock that oxidizes contaminants, but wont rid the pool of bacteria. Compared to chlorinated shock, you can use MPS shock at any time of day and be swimming in the pool 15 minutes later. Its pH neutral so your level wont fluctuate, and by focusing on oxidation, it frees up the pools chlorine to be more efficient at sanitizing.
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Not Brushing Your Pool
You already know how important it is to vacuum your pool regularly to keep scum and gunk from building up and ruining your swim.
But just like your teeth or a hutch of Angora rabbits, your pool needs a good brushing to look its best. Whether you vacuum your pool manually or automatically, follow up with a good brushing.
Signs You Need To Shock Your Swimming Pool
Any pool owner will likely agree, the installation of a swimming pool can help to improve the quality of your health and lifestyle. To continue using and making the most of your pool, clean and safe water is essential. Keeping the water sparkling is as easy as regular maintenance, monitoring and the occasional shock.
In this article, were going to take a closer look at pool shock, including how often to shock your pool, the best day and when. To begin, lets take a look at some of the tell-tale signs that your pool needs to be shocked.
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Shocking Your Pool Faq
When is it time to shock your pool?
- Every couple of weeks during the swimming season.
- When your pool is outside of the recommended free chlorine levels of 1-3 ppm. Shocking your pool will raise the chlorine level.
What about a salt pool?
Yes, even salt pools need a little help once in a while. Salt water pools utilize a chlorine generator to convert salt into chlorine. You can adjust the generator to increase the level of chlorine produced to counteract higher chlorine demands caused by contaminants. However, even salt water pools need to be shocked when the generator cannot keep up with a heavy load of contamination.
When should you shock your pool?
Regular pool maintenance is essential for healthy, efficient, and economical pool operation. For best results, experts recommend shocking your pool when these circumstances occur:
How do I shock my pool?
Shocking your pool is a fairly simple process. Before you begin, uncover your pool, skim the pool, vacuum the sediment, and brush the walls, floor and coves. Before adding shock, youll want to protect yourself with the appropriate gear which includes protective goggles, gloves, and work clothes.
When water tests okay, you are ready to go dive right in!
Tips For Using Pool Shock
Along with knowing when to use pool shock, its also important that pool owners understand how to use pool shock correctly. Pool shock is formed of strong, volatile chemicals that should be handled cautiously every time theyre used.
Here are a few general tips for getting the most out of shocking your pool:
- Dont add shock directly to the pool. Granular shock is highly concentrated and letting it settle on the bottom of a vinyl pool liner can quickly bleach it out, leaving unsightly blemishes. Instead, pool shock should be mixed up with water in a five-gallon plastic bucket before being dumped into the pool as evenly as possible.
- Scrub your pool out on a regular basis. Scrubbing the liner of your pool helps dislodge bacteria and other contaminants so that shock is able to access them more easily and the filter can pick them up once theyve been sanitized.
- Use a manual vacuum on algae rather than a robotic pool cleaner. Robotic pool cleaners dont remove algae from the water. Manual water vacuums are able to remove algae from the pool completely as run-off without reintroducing it. With manual vacuuming, youll have less algae build-up between shock treatments.
- Make sure your water pH is stable. Water that is too acidic may look sparkling and pretty, but it will cause gradual corrosive damage to your pools mechanical components and any plastic-based pool parts such as the liner. Use pool chemicals to maintain a pH neutral water that is neither too acidic nor too alkaline.
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Can You Shock Your Pool Too Much
To know whether or not you can shock your pool too much, its important to learn what pool shock is. Pool shock is just the generic term for concentrated chlorine, and it comes in several forms. Chlorine is added to pool water to remove chloramines from the pool that can irritate the eyes, skin, and respiratory tracts of swimmers.
What happens when you add too much shock to your pool is that you have too much chlorine in the water. It takes an extreme amount of over shock to make the pool unsafe for swimming.
However, adding too much shock can prevent you from taking accurate chemical measurements of the pool water. The chlorine causes this effect as it bleaches the test strips. This can lead to a false negative for chlorine and may lead some amateur pool owners to continue to add even more shock.
How Much Shock Do I Need To Shock My Pool
A simple ratio and a standard rule of thumb to follow when you shock your pool is to dissolve one pound of either calcium hypochlorite or sodium dichlor for every 10,000 gallons of pool water. If you are using sodium hypochlorite, i.e., liquid chlorine, the ratio comes out to 10 ounces for every 10,000 gallons of pool water.
If you are not sure how many gallons are in your pool, here is an easy formula:
Length of your pool x width x depth x 7.5 = volume in gallons
Another standard measurement point for shocking a pool is to measure the chlorine by parts per million . To successfully shock a pool, especially one with algae growth, youll need to bring the chlorine level to at least 30ppm.
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Adding Pool Shock Through Your Skimmer
Some pool maintenance mistakes are relatively minor. But since making this one can literally blow up your pools filter system, we recommend avoiding it at all costs.
Combining calcium hypochlorite or dichlor pool shock and chlorine creates a deadly gas. If you have an automatic chlorinator attached to your filter system and you pour the shock into the skimmer, the two chemicals will combine in a very small space.
Tiny chamber + deadly gas expansion = BOOM.
The Optimal Shocking Frequency
Most pool owners will shock once every 1 to 2 weeks this is ideally what you should be aiming for with your pool maintenance schedule.
Youll come across various thoughts on this topic. Some people say you must shock once a week, while others are fine shocking once a month!
Its also important to understand that you cant overshock.
The worst thing that will happen is the pools chlorine level will be temporarily spiked and then naturally burn off after a few hours of sun exposure. Another downside to overshocking is that youll just be wasting your money.
However you do need to be aware of the must shock scenarios that will steer you off your regular shocking schedule.
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When And How Often Should You Do Pool Shocking
Aside from removing chloramines and the presence of algae, here are other times you should shock your pool:
Before and after the swimming season: When opening your pool after a long break or closing it for a few months, you need to shock your pool after balancing the water chemistry. This way, it will be safe to swim in and help clear the water. You should also do it when closing the pool to disinfect the water.
After a heavy rainfall: When rain falls into the pool water, it also drags dust, pollen, air pollution, and algae spores that can cause water discoloration, increase chloramines, and change water chemistry. This isnt always necessary but it is recommended to do this just to be on the safe side.
After a swimming party: The day after a successful swimming party, you will need to shock it because it probably has been contaminated with organic matter such as body oil, urine, feces, or vomit. This doesn’t necessarily mean that it is visible to the eye – it can be tiny particles floating in your pool water.
Continuous sunny weather: When the sun is out, it means the chlorine levels will go down because of the hot temperature. If the water temperature increases to more than 88°F, you will need to shock your pool.
Since the sun weakens the chlorine. Its important to
ALWAYS shock your pool during dusk or evening. This will help make it more effective and keep the free chlorine at the right level.
Now that you know when to do it, how often should you shock your pool?