How To Shock A Hot Tub With Chlorine Granules (Bromine)

Do you know how to shock a hot tub with chlorine granules or bromine? Can you over shock a hot tub? And do you know what to do when you have over shocker your hot …

how to shock a hot tub

Do you know how to shock a hot tub with chlorine granules or bromine? Can you over shock a hot tub? And do you know what to do when you have over shocker your hot tub?

A hot tub can be a wonderful thing. Who doesn’t love the prospect of coming home from a tough day at work and enjoying a nice, hot soak?

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It is a great way to relax and there are a ton of benefits to be had from enjoying a regular dip in the hot tub. Just like anything else in life, a hot tub takes some work and a little bit of maintenance to properly care for.

Over time and consistent usage, there will be organic contaminants that start to build up in your hot tub. Those contaminants are completely normal.

They are things such as lotion, shampoo, sunscreen, makeup, dead skin cells, hair, and anything else that can come off of your body.

When more than one person uses the hot tub, it just multiplies those organic contaminants. That is where shocking your hot tub becomes a necessity. But what is it? What does it do?

While it sounds like it has something to do with electricity, it most definitely does not. It is basically a large dose of oxidizer that transforms the water back into a clean state after being contaminated.

Shocking the water has three main functions. The first is to remove the aforementioned contaminants. They are all completely normal and don’t make you a gross person.

You may be able to help reduce the amount of natural, organic contaminants by showering prior to getting in but most people don’t want to shower before getting into a hot tub and that will only do so much.

Shocking the hot tub also kills the bacteria that can build up within. When bacteria starts to build up, it can lead to discoloration. A buildup of bacteria can also lead to potential illness.

By shocking your hot tub, you can keep those bacteria at bay. Regular testing and chemical additions are a great way to keep them from becoming an issue but sanitizing and shocking are recommended.

Finally, it takes out any bromamines and chloramines. When you think of that “chlorine smell” that may be best associated with public pools, it isn’t the chlorine but the chloramines that you are smelling.

As the chlorine kills the bacteria and removes the contaminants, it starts to produce a waste product. These are the chloramines.

If you opt for bromine as a sanitizer, it too produces a waste product. They might not be as obvious as the chloramines, to the point that you may not notice them at all. Still, you don’t want to be breathing them in.

Can You Over Shock A Hot Tub?

Far too many people assume that they have high chlorine levels without taking a look to see if that is true. They think that they can notice specific things such as skin irritation, a certain smell, or even eye discomfort.

The fact of the matter is that most of those sensations have nothing to do with the chlorine levels. There are other things such as the pH, copper levels, and chloramines that are causing those changes within the water.

To know whether or not you have over shocked your hot tub with too much chlorine, you will have to test the water. There are chlorine test strips specifically made to test out the water.

The Center for Disease Control (CDC) recommends that a hot tub’s chlorine levels should be somewhere between 1 and 3 ppm for optimal use.

When you are done testing the water out, you may need to either add or reduce the amount of chlorine within your hot tub.

What To Do When You Have Over Shocker Your Hot Tub

There are a few ways to reduce the amount of chlorine in your hot tub if it turns out that you do indeed have too much. Some are easier than others and it may take a few applications of any of these to get the results that you want.

The first thing that you can do is simply let it reduce on its own. If you don’t plan on using the hot tub for a while and have levels above 3 ppm, you may not have to do anything at all.

Don’t use it for a day or two and definitely do not add any more chlorine to the water. The chlorine should eventually dissipate on its own, dropping down into the normal levels.

You can even speed the process up a bit by running the jets and taking the cover off of the hot tub. Direct sunlight breaks down and depletes the chlorine, helping to remove it from the hot tub far faster.

Another easy way to get the chlorine levels down is to just drain the spa. This is probably the preferred method if you want to use your hot tub sooner rather than later.

By emptying out the hot tub, you simply remove all of the chlorine with the water. Refill the hot tub with fresh water and then carefully add in the necessary chemicals, making sure to not overdo it.

Test the water again using your strips before you get in. If you don’t quite know how much to add, there are a number of resources that can direct you.

After all, you don’t want to over shock your hot tub and wind up back at square one again. There is one final method. If the chlorine levels are quite a bit higher after a shock or the addition of chlorinating granulates, you can use a neutralizer.

The most ideal method is the first but if you want to use your hot tub soon, this method is fine. It is always recommended that you deplete the chlorine levels naturally if you can.

If you can’t wait, then sodium thiosulfate is a perfectly fine way to do it. Just make sure that you add in the neutralizer at a gradual pace.

Also, make sure that you follow the manufacturer directions down to the letter. Continue testing your pH levels as well to make sure that everything is where it should be.

Hot Tub Shock Types

When it comes time to shock your hot tub, there are four main types that you will find available. It is important to keep in mind that only two of them are really viable when it comes to shocking your hot tub, though.


The technical name for this one is dichloroisocyanuric acid, so it is just a lot easier to refer to it as dichlor shock. In most of the other brands of shock out there, it is the active ingredient within.

The good news is that you can typically just add it right to the water without the need to dissolve it first. Just make sure that you follow whatever manufacturer instructions that are included.

It also contains a smaller amount of cyanuric acid. That means that it is stabilized, meaning it can stand up to the heat of the spa better. Just keep an eye on sanitizer levels.

If your hot tub is outside and not protected by a structure, make sure to shock it at night so that the sun doesn’t eat away at the chlorine too quickly.

Non-Chlorine Shock

When using a non-chlorine spa shock, keep in mind that it is not meant to be used as a disinfectant. It is not meant to kill bacteria. But it does act as an effective oxidizer due to the potassium peroxymonosulfate (the active ingredient) within.

When used on a weekly basis, it can get rid of those organic contaminants such as lotions, skin cells, and more while also clearing the water when it gets cloudy.

Lithium Hypochlorite

There is a chance that you will find this at your local pool supply or hot tub store but that’s probably not likely. It is not widely available since most lithium goes toward the production of lithium ion batteries.

The cost for the material has sky-rocketed, making it more expensive to use this method than it used to be.

If you find it, you can use it, but good luck getting to it. Especially compared to dichlor shock, which is far less expensive, it is just an all-around hassle to go this route.

Calcium Hypochlorite

You may hear this one referred to as cal hypo. It is the most convenient and inexpensive of the options out there. Just make sure that you don’t use it for your hot tub as it is meant for pools.

It is an unstabilized chlorine, meaning it loses almost all of its effectiveness after only a few hours of heat exposure. Due to the heat exposure, that is why you will see cal hypo used for pools instead of spas.

As a side note, make sure that you only use chemicals that are rated for chemical use. You don’t want to do damage to your hot tub using anything else.


How To Shock A Hot Tub With Chlorine Granules Or Bromine

The good news is that, if you have never shocked a hot tub before, it isn’t a difficult process. There are a couple of precautions and basic steps to follow so that you get the full benefit of the shock.

Make sure that you have your shock, some kind of chemical-resistant measuring cup, gloves and goggles for safety, and test strips ready to go before you start.

Take the cover off of the hot tub first and foremost; you will need to keep it uncovered throughout the duration of this process.

When you add in the shock, some of it will need to dissipate out of the water and can’t do so if the hot tub is covered. If you use a thermal blanket or any other accessory that may float in the water, remove those as well.

With the cover removed, you can now test out the pH of your hot tub. Before you shock it, the pH has to be between 7.4 and 7.6. When the pH is too high or too low, it will have an impact on the ability of the shock to do its job.

Adjust the pH if necessary, before continuing. Turn the blower off, but leave the circulation pump on. You want to keep the water from becoming too agitated and prevent that spa shock from gassing away at an accelerated rate.

Safety gear up because shock is a chemical, after all. If you can avoid getting it on your skin, you should. And you should avoid getting it into your eyes altogether. Wearing gloves and goggles is a great idea; cover any exposed skin as well.

If you have your hot tub inside, turn on an exhaust fan or open a window. Just make sure that you have good ventilation before you use the shock.

Again, it is a chemical. Lastly, make sure that you don’t do this on a windy day if your hot tub is outside. You don’t want the chemicals to blow everywhere.

Now it’s time to measure and shock. Never pour it right from the container as “eyeballing” is definitely not an option. Measure out the amount that you need based on manufacturer instructions.

Add in the shock and leave the hot tub uncovered for the first 20 minutes; this will allow the shock to begin to dissipate. If you don’t plan on using the tub in the near future, cover it after the first 20 minutes to prevent further evaporation.

While it may not be fun to think about maintenance, it goes a long way. Keeping your hot tub clean is imperative and will increase the pleasure that you have while reducing the funky smells or cloudy water.

Follow directions on any shock that you get to avoid overdoing and setting yourself back. If anything seems “off” or smells odd, break out the test strips. They will become your friend when determining the state of your hot tub water.

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