How To Use Chlorine Tablets In A Hot Tub

Chlorine tablets are the go-to option for most hot tub owners as they’re more efficient in killing bacteria and keeping the water clean. In addition, unlike other sanitizers, they oxidize slowly, making it easier to balance the water. But how do you use chlorine tablets in your hot tub?

Test the water to determine its chemical composition. Next, read the manufacturer’s instructions to know how many tablets you need. Take into account your tub’s volume and the current chlorine level. Put the tablets in the dispenser and allow them time to dissolve, then retest the water.

This is a big one—stick with hot tub chlorine tablets, as it’s not safe to use chlorine meant for a swimming pool. Let’s dive into the details.

What are Chlorine Tablets?

Pool chlorine tablets to balance the pH of the water for cleaning and maintenance.

Chlorine tablets (on Amazon) are solid pellets of a chemical compound containing chlorine used to sanitize spas, hot tubs, and pools. Once the tablets dissolve in the water, they form a weak acid that efficiently kills bacteria and other harmful microorganisms, making the water safe.

Chlorine tablets have grown in popularity over the years as an effective way to clean and sanitize hot tubs. They dissolve slowly, making it easy to monitor the pH and balance the water with other chemicals.

Sodium dichlor tablets, or simply dichlor, are more suited for hot tubs and are the most commonly used. They usually come in either 1-inch or 3-inch tablets, the latter of which will often need a floating dispenser.

Once the tablets are in the water, they dissolve slowly, oxidizing to form the weak hypochlorous acid that kills bacteria, algae, and other contaminants. 

If you put them in a dispenser, they will bob in the water as it gradually releases the chemicals. Next, test the water to ensure the chlorine level rests within the recommended range of 3 to 5 ppm.

Are Chlorine Tablets a Good Option for Your Hot Tub?

Chlorine tablets are a perfect option for treating your hot tub if you want to maintain a consistent sanitizer level for longer. In addition, they’re a good option even when your hot tub doesn’t get much use, like during vacations or those weekend getaways.

The tablets will slowly dissolve, ensuring your hot tub has a consistent dose of chlorine over time. This reduces the risk of your chlorine levels dropping below the recommended range of 3 to 5 ppm.

Another good reason to use chlorine tablets is they’re cost-effective and the most efficient way to kill bacteria and algae in your hot tub.

What Type of Chlorine is Best for Hot Tubs?

Experts recommend using chlorine granules (on Amazon) as they dissolve faster and allow you to balance the water quickly. You can also use dichlorine (dichlor), although they’re a bit pricier.

Chlorine granules exist in powder form, and you can add them directly to the water for quick results. While you’ll need to measure the correct amount of granules, they often give you more flexibility, allowing you to control the water pH much easier.

If you go for dichlor, you’ll have to test the water for chlorine levels constantly. Remember, dichlor doesn’t come in the form of time-release tablets or sanitizer cartridges.

While you may want to use trichlor tablets in your hot tub, experts strongly advise against them as they’re meant for swimming pools. 

Trichlor tablets usually take longer to dissolve and could damage your tub’s acrylic shell besides leaving dreary, permanent rings around the tub’s waterline. 

You should also avoid using calcium hypochlorite tablets because they don’t respond well to heat and can lead to a pH imbalance in your tub’s water.

Why Not to Use Chlorine Tablets

While some think using pool chlorine in a hot tub is okay, avoid it. Pool chlorine and hot tub chlorine are not the same, as the chlorine used in pools is more concentrated. Here’s why you shouldn’t use pool chlorine in your hot tub:

  • Swimming pools can withstand a dose of concentrated chlorine as they have a large volume of water to dilute it. On the other hand, hot tubs have a smaller capacity, meaning the chlorine will make the water highly acidic.
  • Your tub is generally hotter than a regular swimming pool and can register temperatures up to 104 °F. This is enough to make pool chlorine dissolve faster and more evenly, making the water in your tub horribly acidic.
  • Pool chlorine has certain chemical additives to stabilize it. But using it in your hot tub will take a toll on the water chemistry. It can lower the pH, so it drifts out of the safe range.

How to Use Chlorine Tablets in Your Hot Tub

You want to do everything right to ensure your hot tub is safe for you and your family. Here’s how to use chlorine tablets in your hot tub:

Test the Water pH, Alkalinity & Total Hardness

Testing your water chemistry is crucial before you treat it with sanitizer or other chemicals. You can use test strips or a comprehensive test kit (on Amazon) to determine the pH and alkalinity of your hot tub’s water.

Carefully follow the manufacturer’s instructions to determine the chlorine levels accurately. For example, JNW Direct Pool and Spa test strips (on Amazon) usually indicate light green if the chlorine level falls below one ppm. This means you need to add more dichlor tabs.

Since pH goes hand in hand with alkalinity and affects the total hardness, you also want to be mindful of these readings. But, again, adding chlorine will affect them. 

Determine How Many Chlorine Tablets You Need

The testing strips and the corresponding ppm readings will inform you how much chlorine you need. Remember, the recommended chlorine level should range between 3 to 5 ppm. Anything below three ppm calls for more tablets.

If you own a small hot tub, you may need up to 3 chlorine tablets, while larger tubs can take as many as five tablets. Moreover, depending on the amount of chlorine in the water, you can even use one tablet.

Carefully read the manufacturer’s instructions to know how many tablets you need depending on the capacity of your hot tub and the level of chlorine already present.

Add the Tablets to the Chlorine Dispenser

Insert the chlorine tablets into your floating dispenser. A good spa floating chlorine dispenser can take up to three 1-inch dichlor tablets.

The chlorine will slowly dissolve in the water, which could last up to one week, depending on the water flow and temperature. You can also adjust how much chlorine your dispenser releases depending on how often your hot tub gets used.

Allow the Chlorine to Dissolve

Let the chlorine sit in the dispenser for 2 to 3 hours, then check to see if the chlorine levels in the hot tub have risen. You can leave the water alone if the chlorine levels are modest.

But if you find that the chlorine level has risen too quickly or you’ve gone overboard with the pH, remove the dispenser from the water. Otherwise, adjust the dispenser to release more chlorine if there isn’t enough in the water after 3 hours.

Test the Water Properties Again

Checking the water quality of a pool with the help of a test strip with PH value, chlorine and algaecide

Once you’re satisfied the dispenser has released enough chlorine, test the water again. You’re ready to soak in your tub if the water looks clear enough and doesn’t have that pungent chlorine smell.

How Frequently Should You Add Chlorine to Your Hot Tub?

In general, you can add chlorine to your hot tub every four to seven days. However, the amount of chlorine you add and the frequency depends on your tub’s capacity in gallons and the sizes of tablets you use.

A 20 g tablet of chlorine can take three days to one week to dissolve if the water circulation and temperature are favorable. So for an 800-liter (211-gallon) or 4-person hot tub, you can add two dichlor tablets weekly.

You can’t go wrong with three chlorine tablets weekly if you own a 1000-liter (264-gallon) hot tub. While this volume seems enormous, a floating dispenser will help even out the process, ensuring you don’t use excess chlorine.

If you get your hands on dichlor tabs with no precise time-release specifications, you might want to keep an eye on the water pH. Test it regularly with pH strips (on Amazon) to know the ideal intervals between which you should add chlorine.

You only need enough chlorine to keep your water safe; adding it too frequently will lower the pH to harmful levels. When the pH dips too low, the water is too acidic and will irritate your skin, besides burning your eyes.

Moreover, it can discolor the tub’s floor and corrode your pipes. And if the effects become too severe, you’ll incur heavy replacement costs.

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