How Much Chlorine Do You Need For A Hot Tub?

Maintaining a hot tub calls for some dedication, since the water needs to be kept in good condition to prevent it from becoming a breeding ground for germs that can cause water-related illnesses. As the CDC's aquatics expert, Michele Hlavsa points out, "We often underestimate what it takes to properly run a pool or hot tub to maintain a chlorine level where it needs to be," per WebMD.

Most of the work involved in looking after your hot tub lies in maintaining your water's delicate balance, which is determined by its pH quality. If its pH is too low, the water becomes more acidic, which will irritate your skin and eyes and can cause your tub's pipes to corrode. Too high, and the water will not be clean, allowing germs to thrive, explains Master Spas. According to the CDC, it's important to ensure that pH levels stay at a sweet spot which is between 7.2 and 7.8.

Closely related to your pH levels is the amount of sanitizer you need to use to keep your water germ-free. Swim University says there are a number of options, including chlorine, bromine, biguanide and salt systems. Of the three, chlorine is the most commonly used, as well as the easiest to manage.

Before you dash out to pick up a random container of chlorine, know that pool chemicals and hot tub chemicals can't be used interchangeably. As Arctic Spas point out, not only are pools bigger than hot tubs, but they are also much cooler, and because of this, Hot Tub Warehouse recommends the use of sodium dichlor, which comes in granules. Not only does it dissolve evenly in hot tub water, but it also doesn't react to the water's high temperatures. 

The best way to use sodium dichlor is to mix the granules in a bucket of clean water and then add that to the hot tub. While throwing granules into the hot tub directly is an option, it isn't recommended because the chemical could interact with the acrylic in your hot tub, changing its color in the process. So, how much chlorine do you need to get your hot tub to where it needs to be?

If your hot tub is new, Aqua Warehouse suggests you will initially need to add more chlorine than you would need to use on a regular basis, in order to get your water's pH level to where it needs to be and give the sanitizer a chance to sweep through the different parts of the hot tub's plumbing and pumping system. The method, known as shocking, is meant to boost chlorine levels so any unwelcome bacteria is killed off before the new tub is ready for use. Your hot tub manufacturer should recommend how much chlorine to add to your spa, but if it doesn't, a good rule of thumb is one teaspoon of chlorine for every 100 gallons of water.

Once your hot tub has been shocked, adding chlorine granules becomes a weekly task, which can only be determined if you test your water regularly. The quantities, in this case, aren't exact. To find out how often — and how much — chlorine should be added, you'll need to test your hot tub water at least two or three times a week, per Poolarama. Your hot tub's chlorine levels should be kept between 1.5 to 3 ppm.