Testing your spa water is a quick and easy process.

Your new hot tub will be your backyard oasis—the place to escape and relax any day of the week and any time of day. As long as you take care of your spa, it’ll be there to take care of you.

Fortunately, hot tubs don’t require much care. The biggest responsibility you have will be keeping the spa water clean. Chlorine is a standard hot tub water purification method. While innovative water care innovations, including saltwater systems, improve specific aspects of hot tub water care, they are often only available on luxury and premium hot tub models. Chlorine remains a tried and true method of keeping hot tub water clean for all spas, from entry-level to high end hot tubs. Why? Because it works.


Much of the “contamination” that you’ll need to prevent or remove from your spa water is one form or another of microbial life. Various types of bacteria, archaea, protozoans, and fungi like hot water as much as people do. Adding chlorine to spa water works because it creates an environment that’s hostile to microbial life.

When chlorine and water are mixed, the result is a solution that includes hypochlorous and hypochlorite acids. These weak acidic compounds damage or destroy essential parts of most bacteria, including enzymes, nucleic acids, cell walls, and membrane lipids. At the same time, chlorine levels deadly to bacteria are hardly noticeable to humans.

When chlorine kills bacteria, it leaves behind some traces of the struggle. These traces, known as chloramines, cause the “chlorine smell” that people sometimes associate with spa and pool water. The best way to reduce the smell is to change your spa water every 3 to 4 months, which will get rid of all chloramine buildup.

It’s a good idea to test your spa water at least twice a week when using chlorine.


In order to eliminate water bacteria in your new spa, you’ll need to maintain specific alkalinity, pH, water hardness, and chlorine levels. Fortunately, doing so isn’t rocket science. All you’ll have to do is test your spa water regularly and adjust as necessary.

Hot tub manufacturers use technology to simplify hot tub maintenance. In-line systems integrated into the spa shell use pre-filled mineral and chlorine cartridges to automatically dispense sanitizers. Color-coded test strips purchased from your local hot tub dealer assess the alkalinity, pH, water hardness, chlorine levels, and overall condition of the water, while bottled or powdered water care products, also available from your dealer, allow you to adjust as necessary.

If you’re a visual learner, check out this short video that describes testing your water’s chemical levels.

Testing your spa water is as easy as lifting the cover.


With your test strips and recommended spa water care products in hand, you’ll first test the water’s alkalinity. Alkalinity is a measurement of how well your water neutralizes acid. The higher the alkalinity, the more acid it will take to lower your water’s pH. The pH of spa water is important because chlorine works best at eliminating bacteria at a certain pH level (more on this below). Be sure your spa water is warm when you test it.

Dip your test strip into the water and compare the color of the strip to the color on the product packaging to interpret the reading. Consulting your packaging is especially important if your test strip measures multiple water conditions at once. The color of your test strip will let you know if the alkalinity level is too low, too high, or just right.

The alkalinity level should be between 80 and 120 parts per million (PPM). If it’s not in that range, you’ll have to adjust it. Sodium bicarbonate will raise the alkalinity level; sodium bisulfate will lower it. These products, packaged by various manufacturers, are sold under names including “spa up” and “spa down” and “alkalinity up” and alkalinity down.” You should always use the product recommended by your spa’s manufacturer. If you’re unsure, consult your local dealer, who is an expert in hot tub water care.

Enjoying clean water in a pristine spa.


After testing and adjusting alkalinity levels, use the same test strip to check the pH level of your spa water. pH describes how acidic or “basic” your water is on a scale from 0 to 14, with 7 being neutral. Numbers below 7 describe acidic substances, while numbers above 7 describe basic substances. Chlorine destroys bacteria best when the pH level is between 7.2 and 7.8, which is slightly more basic than true neutral.

If your pH level is outside the acceptable range—and you’re sure your alkalinity levels are correct—use the pH up or pH down product that your manufacturer and dealer recommend to coax it back to the right level.

While various products may work to adjust your pH, it’s always best to use products manufactured by or at least approved by your hot tub’s manufacturer. Always check with your local dealer before using any product in your hot tub.

Making sure the hot tub’s good to go.


After you’ve tested and adjusted your spa water’s alkalinity and pH levels, the next step is to check your water’s hardness. Hardness refers specifically to the amount of calcium and magnesium in the water.

Water hardness results directly from the mineral content of your water source. That means, if your tap water comes from a municipal well with high levels of natural calcium, you’ll likely have hard water in your hot tub. Hardness will not change much as you soak over time; it will only go up or down when you add or remove water, or add or remove calcium.

The ideal amount of calcium and magnesium in your water is between 175 and 275 PPM. If you have too much of either, your water will not hold chlorine effectively. Scale may begin to grow on the spa shell and in its plumbing, and your water may be cloudy. Products such as Vanishing Act and the Clean Screen™ pre-filter can lower calcium levels.

If you have too little calcium, the shell, plumbing, and jets may all experience corrosion from the soft water. Fortunately, the remedy for this is simple: add calcium. Your local dealer will show you approved calcium products to use in your hot tub.

Clean water is the key to enjoying your hot tub.


Too little chlorine in your spa will give bacteria a foothold; too much chlorine could irritate spa users and potentially damage some spa parts. The test strip you used to check other levels will also indicate if your spa contains too much, too little, or just enough chlorine. The chlorine range should be between 1.5 and 3 PPM. Typically, adding chlorine powder to your water every other day will keep your spa water within range, but always test to ensure you add the proper amount.

FROG® @ease® In-Line System with SmartChlor Technology

For an even simpler way to add chlorine and condition the spa water, consider purchasing a spa with a built-in in-line system. Hot Spring is one of just a few manufacturers to feature this key benefit on their Hot Spot spas.

How the @ease® System Works

The system uses two pre-filled cartridges that fit in a convenient in-line housing that is part of the spa’s plumbing system. The @ease SmartChlor cartridge slowly releases chlorine to sanitize, and the mineral cartridge releases minerals, including silver, that also kill bacteria and help condition the water for a softer feel.

Frog ease filter system.

Learn how to troubleshoot your spa water.

A warm soak in crystal-clear water.


To make sure nothing overwhelms your base layer of chlorine, it’s a good idea to “shock” your spa once a week and after it’s been used by many hot-tubbers at once. Shocking your spa means giving it a large dose of chlorine to break down any buildup of contaminants that can cause an odor or cloudy water. Your dealer can direct you to manufacturer-approved spa shock products.

Keeping your new hot tub in pristine condition comes down to testing your water regularly and adjusting it as necessary. Just a few minutes of light work each week is all it will take to enjoy the benefits of your spa whenever the mood hits you. Test strips and adjustment products are available as kits from your local dealer, who is also always on hand to answer any questions you have about your spa.

At Hot Spring®, we believe that the time you spend in your spa should be the best part of your day. That’s why we work hard to simplify the hot tub water maintenance process, whether you choose a chlorine system or another water care option. To inquire about hot tub pricing, request a quote.