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When people think of spa chemicals, they typically think of chlorine and bromine products used to sanitize hot tubs. But there are other spa chemicals and water care solutions that are just as important for maintaining a clean, comfortable, and sanitary hot tub.

The water that comes from the tap often contains dissolved calcium that can build up on the hot tub shell and inside of pipes. Metals in the water can interact with chemical stabilizers and turn the water a range of unappealing colors. Metals and calcium need to be removed from the water as you fill your spa to prevent residue from building up on surfaces, as well as to prevent chemical interactions. Additionally, the water must be treated to ensure the pH and alkalinity levels are within the correct tolerances for subsequent water treatment to work correctly.


The water chemistry right out of the tap can vary from place to place, even within the same city. Certain neighborhoods may have older pipes that allow iron or copper to dissolve into the water. If your home isn't tied into the municipal water system, then you likely draw your water from a well on the property. Metals such as iron and manganese are common in well water. These metals can interact with chlorine to discolor your spa water—turning it to green, turquoise, even pinks and purples. The best way to avoid unwanted chemical reactions is to remove metals and calcium when you're filling your spa.


The Clean Screen® pre-filter from Hot Spring® Spas attaches directly to the end of a garden hose and filters out metals, including copper and iron, before they can enter the hot tub. With this convenient filter, fresh water is what flows into your spa. It also filters out organic contaminants that can cause foam to form and tannins that can discolor the water.

This is an important first step to ensure that your spa water remains clean and clear. Without a pre-filter, you may find yourself having to change your spa water more often than would otherwise be necessary. Starting off with clean water also sets up your spa so that chemicals will work as intended to treat and sanitize your spa water.


Oftentimes, water also contains dissolved minerals, such as calcium. In high enough concentrations, these elements can be deposited on the interior of spa pipes and pumps, restricting water flow and shortening their life. Calcium can also be deposited on a hot tub shell, where an unpleasant layer develops as a result. Reducing calcium levels will extend the life of your hot tub, result in silkier water, and prevent an unpleasant build up on the surfaces of your hot tub.

Hot Spring offers easy ways of removing calcium from your spa. The first step is to fill your hot tub with the Clean Screen and to use the recommended spa chemicals to balance your water. If you have a spa from the Highlife® Collection, you will simply place the Vanishing Act® calcium remover over the heater return in order to filter out calcium. If you have a spa from either the Limelight® Collection or the Hot Spot® Collection, you can install a suction fitting to absorb dissolved calcium from the water. It is available in two sizes for smaller and larger hot tubs.

Another convenient option is the On the Go® portable water softener. It simply hooks up to your garden hose and, as the water flows through the softener, it removes calcium. This water softener is so effective that your water calcium levels may even drop below what is recommended. Periodically, test the water flowing out of the On the Go softener with test strips to see where the levels currently are. If they drop below what is recommended, simply continue filling your spa until full, and then top it off with water straight from the hose.


Once your spa has been filled and powered on, it's time to test and treat your water and get it ready for use. You'll need to have the following materials available from your local Hot Spring dealer handy in order to get it set up correctly:

  • FreshWater® 5-way test strips
  • FreshWater Salt Test Strips™ if your spa is equipped with the FreshWater Salt System*
  • pH Up and pH Down chemicals to adjust the water's pH and alkalinity
  • Chlorine to shock and create a residual chlorine reading

The first step is testing with FreshWater test strips to check your spa's pH, alkalinity, hardness, and free chlorine level. The 5-way test strips make this process fairly quick and simple: you'll dip the test strip into the water and compare the color that appears on the strip to the color scale on the package. This will give you a working range for the total pH of the water, alkalinity, and the parts per million for calcium and chlorine.

Calcium tolerances for hot tubs that are equipped with the FreshWater Salt System are lower than those that are set up for traditional chlorine or bromine sanitation, so be sure that you are using the correct strips for your spa model. Your local hot tub dealer can help you make sure you have the correct supplies to get started.

Once you've determined what the current chemical composition of your fresh hot tub water is, you can make adjustments with chemicals to bring into the proper operating range. Hot Spring spas have the following recommended ranges:


Free Chlorine 1.0-5.0 ppm
Water pH 7.2-7.8
Total Alkalinity 40-120 ppm
Calcium Hardness Standard: 75-150 ppm
Salt System: 25-75 ppm

If your water is out of any of the recommended ranges, then Hot Spring provides the proper spa chemicals that allow you to adjust the water as needed. Consult the owner's manual for your particular spa model to determine the amounts you will need to make adjustments and get your hot tub water ready for use.

You can adjust water pH and total alkalinity with pH/Alkalinity Up and pH/Alkalinity Down. You can raise the chlorination levels by introducing measured chlorine (liquid or granular) into the water. If your spa is equipped with the optional FreshWater® Salt System, follow the start-up instructions located in your FreshWater Salt System Owner's Manual.

Once you've added these spa chemicals, your spa is ready to operate.


Spa chemicals and water care go well beyond simply adding chlorine. Filling your spa with soft, balanced water does more than prevent stinging eyes and dry skin. It keeps your spa water fresh and refreshing so your hot tub remains a relaxing refuge from stress and worry right in your home. At Hot Spring Spas, we believe in providing the Absolute Best Hot Tub Ownership Experience®, and we make sure to provide you with the most convenient and effective hot tub water treatments, spa chemicals, and water care devices that make maintaining a perfectly balanced, clean, and relaxing hot tub easy.

We are committed to manufacturing innovative hot tubs that you can easily maintain, so they are always ready for a soak right at home. To learn more about hot tub water care and the spa chemicals and options we offer, contact your local dealer today.

*The FreshWater® Salt System cannot be used on Hot Spring Hot Spot spas or any Hot Spring hot tubs manufactured prior to 2019.