How Often Does Hot Tub Need Chlorine [August 2020]


The best way to know how often you need to add chlorine is to regularly measure it. After that, you can easily calculate how much chlorine (sodium dichlor) you need.

Consider adding more chlorine if you need to temporarily increase the free chlorine level to 10 ppm.

It is important to know that you only need a small amount of chlorine in order to successfully sanitize your hot tub, so it is very easy to overdo it if you are not careful.

Having too much chlorine can cause damage to your hot tub and affect your skin, eyes, and lungs. Luckily, decreasing the chlorine levels in your hot tub is very easy to do. In fact, you may not even have to do anything at all.

How Much Chlorine To Add To Hot Tub First Time

It can take some time before you can find the perfect amount of chlorine needed for your hot tub and that’s OK.

Shocking a hot tub requires about 2 ounces (4 tablespoons) of chlorine for every 500 gallons of water.

You need to make sure to test your chemical levels often and keep an eye on the chlorine level at all times and make sure it doesn’t drop below 1 ppm. 

The truth is that you actually want to keep that at 3 ppm. The higher end of the recommended ranges the better. Depending on how often you use your hot tub and how many bathers you usually load (several people use it), the hot tub nation highly recommends sticking with chlorine spa shock in order to kill bacteria and keep the water sanitary.

Bonus reading

All About Your Water Chemistry

Chemistry, if not managed properly, can literally make you sick. Don’t let that be you or your family. Head over to this article which took me some time to complete, but even I go back to it from time to time to remind myself.

Is It Safe To Go In A Hot Tub With High Chlorine

You have to be aware that having too much chlorine can damage your hot tub and affect your skin, eyes, and lungs. Thankfully, reducing the chlorine levels in your hot tub is very easy to do. As a matter of fact, you might not even have to do anything at all. 

In case you are facing the high-chlorine situation, and you want to use your hot tub soon, then you could try a neutralizer. I found recommendations that allow the sanitizer levels to break down naturally. However, if you have to use your hot tub, then what you can do is you can add sodium thiosulfate to the water. Sodium thiosulfate (Affiliate link, in case you are interested in solving this issue) will break down both chlorine and bromine in your water fast so you can soak sooner.

Hot Tub Chlorine Levels Keep Dropping

Your chlorine level dropping that quickly usually means that the chlorine is getting used up on something that’s in the water. Try increasing your dose of chlorine until you oxidize the contaminants and start maintaining a chlorine reading. 

Metals in the water will chew up chlorine as well as residual soaps from swimsuits ect. 

You can try a clarifier and then cleaning your filters super well in order to remove any contaminants/waste from the tub. Bad smells can also be a sign of contaminants. Sensing strong chlorine means that you don’t have enough chlorine as strange as it sounds. 

Can You Use Pool Chlorine In A Hot Tub

Despite what would seem to make sense, you shouldn’t really use pool chemicals in your hot tub. Hot tub chemicals are way less concentrated than those made for pools, even though they are the same material. I am going to list a few reasons to avoid putting pool chemicals in your hot tub:

  • Pool Tri-chlor tablets are extremely acidic. While it won’t have a negative effect on pool water, being extremely acidic destroys the hot tub’s water’s total alkalinity’s buffering capacity which results in a severe drop in pH.
  • Soda ash is another chemical that can disrupt the alkalinity of hot tub water which potentially leads to a big spike in pH. It has happened that the pH reached as high as 13, making it extremely dangerous to soak in. Once that happens, it could be hard to restore the perfect pH balance afterward despite adding acid to lower the pH.
  • Liquid chlorine contains a lot of salt. To be specific about it, there is one pound of salt per one gallon of chlorine. Adding this high amount of salt to such a small volume of hot tub water will increase the hot tub water’s alkalinity, pH and water hardness. This can cause the level of dissolved solids in the hot tub water to also increase. The abundant dissolved solids lead to more frequent draining and changing of the water, and it can also lead to increased scale and possible filter and equipment failure.

Best Chlorine For Hot Tub

The way chlorine works is that it oxidizes contaminants, attacking and destroying them from the inside out. As the chlorine dissipates it turns into a waste product called chloramines. This is what’s causing the stinging, drying, and gives it stinky reputation chlorine has, which reduces the sanitizer’s effectiveness.

In order to keep chloramines in check, you’ll need to add chlorine on a regular basis, which usually equates to at least once a week. In case things go south, though, and the chlorine isn’t working on its own, you would have to shock your hot tub to get rid of chloramines. That too needs to be done on a regular basis, in order to keep your water clear and pristine.

Now, this chlorine (Recommended product – Amazon link) will do just fine since it provides stability and is highly effective The link will take you to Amazon to check the latest price.

How Long After Adding Chlorine Can You Use Hot Tub

Generally speaking, you should not get into your hot tub right after adding chlorine or other chemicals really due to the high concentration of it in your hot tub water. Give it some time for the chemicals to dissipate and to disperse fully in the hot tub water in order to avoid any concentrated areas of the chemical.  

This shouldn’t take too long but it’s best to be safe and give it about 30 minutes or so. 

Then you can put the jets on to allow the water in the hot tub to circulate around and for the chemical to be fully absorbed. It’s also not a bad idea for the hot tub cover to stay off during this time as this will allow for any vapors to escape more quickly. 

I have another article specifically targeting hot tub covers if you would like to read about it.

In case you are using chlorine in your hot tub as a sanitizer then you will add enough to the water until it is between 5 and 8 ppm. This will allow the water to get a good chlorine boost and the chlorine itself can then really work hard to get rid of any bacteria and to help to cleanse the water. 

However, it is not safe to bath while the chlorine hot tub levels are between 5 and 8 ppm and it is likely that it will cause irritation to your skin and eyes and potentially cause some respiratory issues. 

All of this really means that you should wait before heading back into the hot tub water. Chlorine’s ability to decay over time is amazing so the amount of chlorine in the water will for sure reduce as you are waiting. Keep checking your chlorine levels regularly and wait for the levels to be between 2 and 4 ppm in order for it to be safe.

So this article answered the question of how often does hot tub need chlorine and hopefully you will never have issues caused by a high concentration of chlorine. As long as you stay away from the hot tub until the chlorine levels take a dive, you should be fine.

Editorial Staff

I'm Adnan Sabanovic, the guy behind Hot Tubs Report. I've had a chance to enjoy hot tubs last few years and have really become interested in owning one of them. Nearly every weekend you'll find me spending time with my family or playing sports. If I am not doing that then I'm here writing about tubs on Hot Tubs Report. This blog is a research for my first hot tub which I decided to document and share publically so others can benefit from it as well.

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