Have you ever seen an abandoned pool?
If you have, you know how disgusting that stuff is. That’s why it’s important to keep your pool clean and your pool water chemistry in check. How do you do that? One thing you need to do is shocking your pool. Also read our complete guide on pool cleaning basics.
What does that mean? How can I do that? That sounds dangerous. (It’s not)
Worry not, because we’ll talk you through how to shock your pool in a way that allows you to swim in your pool within 30 minutes, so stay with us!
What Does Shocking Your Pool Mean?
Shocking your pool means introducing chemicals that oxidize chloramines in your pool water. It’s also another way of saying super chlorination.
When you shock a pool, you’re putting in chlorine to clean and sanitize the water to remove chloramine buildup and kill bacteria.
Chloramines are what you get when chlorine mingles with substances from the human body naturally, like sweat, oil, or (ugh) urine.
This is what naturally happens when chlorine sanitizes your swimming pool. Chloramines are that strong chlorine smell you catch a whiff of at hotel/public pools.
Shocking can also help with the look of your pool by clearing up cloudy water. It also helps eliminate algae growth if that’s a problem.
If you’re not a big fan of using chemicals for your pool, we’ve created a guide for you on how to maintain a clean pool without the use of chemicals.
When Should You Shock Your Pool
Shocking should be done at specific times or before/after certain events.
Below we have written down a simple general guideline of when you should get around to shocking your pool.
When Pool Water Free Chlorine Levels Are Not in the Ideal Range
How would I know these levels? There are a few options you could take.
- You can get liquid test kits
- There are quick and easy test strips you can buy
- Certain pool stores offer water sampling services done by a pool professional
When the test shows that your free chlorine level falls outside of the ideal 1-3 PPM or parts per million, it’s time for a pool shock.
Testing sounds like effort. That sounds like spending money.
I hear you. But let’s say you’re some regular guy with a pool. You’re not some public pool or a hotel or whatever. There’s a fairly simple layman’s way of telling when it’s time for a shock.
What is this method? Sniffing around.
If it smells like that pool-chlorine-smell, then that means the chlorine has combined with the various bodily liquids in the pool and is no longer capable of sanitizing the water.
At the Start of Pool Season
Before you let people in your pool, you must make sure that your pool is clean.
There are a few standard procedures most people follow before opening a pool, and one of them is applying a pool shock.
A double dose of shock is recommended for a pool that hasn’t been used in quite a long time. That is around 2lbs of pool shock per 10,000 gallons of water.
Weekly Maintenance
Weekly?!
Well, not necessarily. But if your pool sees a lot of use. A weekly shocking for the sake of maintenance is recommended.
However, if your pool doesn’t get much use and there hasn’t been any extreme weather lately, you can afford to be a little lax with maintenance.
Speaking of heavy use and extreme weather…
When It’s Gone Through Heavy Use
We already mentioned that bodily fluids that naturally come from a person’s body, like sweat, can interact with chlorine and change its composition.
And to put it simply, pools get gross when many people use them.
So it’s generally a good idea to clean all the organic contaminants up when you have had heavy pool use in the past few days.
After Heavy Rain
Rain can carry impurities to your pool when it pours.
Not to mention acid rain also exists.
All that can change the pH level of your pool, so shocking your pool is a good way to reset that balance that your pool had.
After Extremely Hot Days and Extremely Sunny Days
When it gets really hot and that temperature starts soaring, your chlorine can get weaker.
And during a sunny day, the sun’s UV rays can dissolve your chlorine.
With all these combined, you leave space for bacteria to grow and throw a pool party of their own in your pool.
At the End of Pool/Swimming Season
It would be best to shock a pool before you close up until the next season.
This will ensure that you’ll leave it with some chlorine to keep your pool clean for a good period.
Sure it won’t keep it 100% clean for the entire time it’s closed, but it’ll keep it LESS dirty and suppress pool algae growth.
Types of Chlorine and Types of Shock
There is more than one type of chlorine and more than one type of shock.
Knowing the differences between them can help you decide which types would suit your swimming pool.
Types of Chlorine
These are the different types of chlorine to look out for!
Free Chlorine
Or FC is what people call the chlorine that can keep your water clean. Your free chlorine levels should be around 1-3 parts per million, as we previously stated, for optimum cleaning.
Combined Chlorine
Combined chlorine (CC) is the amount of chlorine used up from cleaning.
It can’t do much in sanitizing your pool anymore and is ineffective in getting rid of harmful bacteria.
Your combined chlorine level should be less than 0.2 parts per million.
Total Chlorine
Total chlorine (TC) is the sum of all the chlorine in your pool. So that’s your free chlorine and combined chlorine altogether.
Testing methods can generally give you the number of your FC and your TC. On the other hand, combined chlorine is deduced by subtracting your FC from your TC.
Breakpoint Chlorination
Breakpoint Chlorination is when there are enough FC in your system to break down the chloramine bonds.
You need to add FC ten times the amount of the CC in your pool to achieve breakpoint chlorination. Free and combined chlorine numbers are important to the breakpoint.
Types of Pool Shock
These are the different pool shocks to consider when looking for one!
Calcium Hypochlorite
This usually is called cal hypo for short. This particular shock has been used to disinfect swimming pools for a long time. It’s quite a common and cheap way to shock your pool.
It’s also good for low pH level pools because it has a high pH level.
- Contains 65%-75% chlorine
- It would be best to dissolve calcium hypochlorite before it can be applied to your pool.
- Needs to be used after the sun goes down
- It adds approximately 0.8 ppm of calcium into your water per ppm of FC added; keep this in mind if you already have high calcium in your water chemistry
- It will take around 8 hours before you can swim in your pool again
Lithium Hypochlorite
This is the alternative to cal hypo. If you have the calcium hardness level problem mentioned above, cal hypo may not be the best shock for you.
Instead, you could go with a lithium hypochlorite shock. It dissolves faster than cal hypo, so you don’t need to pre-dissolve it.
- Usually contains around 35% chlorine.
- Needs to be used after the sun goes down
- It will take around 8 hours before you can swim in your pool again
- It can be toxic to aquatic life, so you need to be careful when you dispose of water treated with lithium hypochlorite
- Due to the above point, it is ideal to get rid of algae bloom
Dichlor Shock
The full name is dichloroisocyanuric acid. There are types of dichlor shock that can be applied directly to your pool.
This shock is also stabilized, which means it contains cyanuric acid.
This type of shock is also appropriate for saltwater pools.
- Contains 50%-60% chlorine
- Usually doesn’t need dissolving
- It adds 0.9 ppm of cyanuric acid with every ppm of added FC
- It will take around 8 hours before you can swim in your pool again
- Needs to be used after the sun goes down
Non-Chlorine Shock
You may be thinking, “all of these shock treatments will take 8 hours before I can swim safely! What happened to the title of this article?“
We didn’t clickbait you or anything, and we’d like to direct your attention to this treatment. A non-chlorine shock is a chlorine-free shock. I know, shocking, isn’t it?
It uses potassium peroxy monosulfate, a fast and inexpensive choice when looking for non-chlorine-based pool shock. This is what’s used in saltwater shocking.
- You can apply it directly to the pool water at any time
- It will only take roughly 15 minutes before you can safely swim again
- Therefore, it does not contain any chlorine and would not be useable as an algaecide.
How to Shock Your Pool
With that all out of the way, let’s get into the meat and potatoes. How do you shock your pool?
Follow the step-by-step instructions below, and you’ll be on your way to shocking pools like a master in no time.
Test Pool Water
First, before you do anything, it’s a good idea to test your chlorine levels. You’d usually have to test your chlorine level to determine whether you should shock in the first place.
It would help if you also do a quick pH, calcium hardness, and alkalinity levels check with your chlorine levels.
Ideal levels for pH are around the 7.4-7.6 range and 100-150 parts per million for the alkalinity.
If you have vinyl liner pools, the calcium hardness should be around 175-225 parts per million.
Concrete or plaster pools should be around 200-275 parts per million.
Prepare Shock, Pre-dissolve Pool Shock
Different brands and manufacturers may have different specifications and instructions for their shock products.
They usually will have instructions on the package to calculate the portions for your pre-dissolve.
Usually, it’s recommended to fill your bucket 3/4ths of the way with warm water. Pour in the shock and stir until it’s as dissolved as possible.
Unlike chlorine shock, other shock products like the non-chlorine shock can be applied directly without going through the pre-dissolve process.
Pour the Shock in Your Pool Water
Apply your shock one bag at a time if your product doesn’t need dissolving. Repeat this until you’ve reached the breakpoint that you calculated.
In this step, keep your pool filter and pool pump running at full speed. The filtration system will help mix in the shock to the pool water.
The filter system will act as an oversized blender. How fun.
Keep the system running for around 8-12 hours even after applying the shock.
Walk around your swimming pool as you pour the good stuff in to evenly spread the pool shock into your pool.
If you can still spot some solid particles or granular chlorine in your pool shock, try to get something like the net or the bucket to stir that part of the pool until it completely dissolves.
After that, you’ll have to wait for the pool shock to settle. The time to wait will depend on the manufacturer’s recommendations.
Saltwater Pool Shock Guide
Saltwater pool owners should take a different approach to shock treatment for their pools. The chemical makeup of a saltwater pool would be different from a regular pool.
The salt would pass through a generator, and it turns into chlorine. So you’d already have enough chlorine in your systems. It already has naturally higher free chlorine levels.
So it’s recommended that you use non-chlorinated shock for your pool or a dichlor. As we mentioned above, this is usually used for saltwater pools.
With a switch flip, some saltwater generators can bump up your pool chlorine count.
Like most pools, it’s a good idea to shock them according to the guidelines written above on when to shock a pool.
Safety Guidelines When Handling Pool Shock
Many things could go wrong when handling pool shock. When mishandled, liquid chlorine and granular chlorine used in chlorine shock could become dangerous substances.
We’re talking about the possibility of explosions here. Do not play around with these substances.
- 🚫 DO NOT add shock to your pool skimmer. Some skimmers come with an automatic chlorinator, and pool shock combined with chlorine could lead to explosions.
- 🚫 DO NOT breathe in these substances. As much as possible, wear a chemical mask when handling these chemicals as accidental inhalation could devastate your respiratory system.
- 🚫 DO NOT mix different types of shock. Mixing these substances could cause a volatile reaction, so don’t be hasty and add them separately. Granular shock mixed with liquid chlorine especially shouldn’t mix.
- 🚫 DO NOT add shock directly to your pool. As we have indicated above, certain types of a shock need pre-dissolve. Some don’t need it, and you should keep in mind which is which.
- OBSERVE SAFETY when handling these substances. Wear protective gear such as goggles and chemical-resistant gloves. Certain shocks can produce some dangerous byproducts.
Frequently Asked Questions (FAQs)
Do you still have some questions floating in your head? Let us help you answer them with some frequently asked questions answered below.
You would usually conduct a pool shocking at night. As we mentioned before, the UV rays from the sun could react with chlorine and decrease effectiveness.
So the nighttime is the best time. And as long as you’re not trying to take a nighttime dip, no one usually uses the pool at night, leaving it undisturbed to do its thing.
It depends on your pool’s size, but it shouldn’t take too long. It may take an hour or less. However, you should make sure to let your shock settle.
A good majority of shocks will recommend waiting at least 8 hours before taking a dip in your pool again. Some may even recommend 12 hours or so.
But chlorine-free shocks allow you to wait for way less than that. With non-chlorinated products, you can swim in your pool again as fast as 15 minutes later.
On the contrary, you should keep the pumps and filtration on while doing your shocking. The pumps and filters will serve as a circulator, acting as a mixer or blender for your pool while you’re pouring your shock in. It’ll help with mixing the shock in faster.
Keep Clean, and Happy Swimming
Now you know how to properly and, more importantly, SAFELY go about your shocking process.
Things to keep in mind when you’re shocking your pool is:
- When to do your shocking
- Your types of pool shock
- The proper steps to conducting a pool shock
As long as you keep these in mind, you’ll be able to keep your pool safe and clean. Remind the kids getting in your pool to answer the call of nature elsewhere.
Thanks for reading, and we hope you now know how to shock your pool with ease and security!
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