How To Add Spa Chemicals

At first glance it appears that spa owners need to keep a bewildering array of spa chemicals to keep their hot tub operating correctly and clean. As well as the chemicals they need to know how to use the various test kits that come with their spa.

Add Chemicals to a Warm Spa

When chemicals need to be added to a spa you should have it running at the slowest speed to encourage the chemicals to be fully dissolved and evenly distributed. Do not add chemicals while the spa is in use.

Understand your Chemicals

Make sure that you know what each chemical does so that you will always choose the right one in response to a test result.

PH Value

The test results for PH value should read between 7.6 and 8.2. If the results are different, you must add the chemical necessary to raise or lower the value until it is within that range. Always add chemicals in small increments and re-test after waiting ten minutes for the chemical to take effect.


The test results for alkalinity should read 100. Add the necessary chemical if you get a different result.

Sanitizing the Water

You will be using either bromine or chlorine to sanitize your water. Test for whichever chemical you are using. Make up any deficit revealed by the test. Do not try to use both bromine and chlorine.


You can fit an ozonator to your spa which will convert oxygen into ozone and feed it into your spa water through the normal action of the spa pump. The ozone will kill off most bacteria so you will be able to keep the bromine or chlorine levels at the lower end of the scale in the test results and use less sanitizer. Using less chemicals will make balancing the various test results much easier.

Clarifying the Water

If the water in the spa is appearing cloudy, add some spa water clarifier. The clarifier encourages impurities and bacteria that are suspended in the water to clump together so that the filters can remove them.

Other Chemicals

There are chemicals you can add to remove stains and prevent scaling but they do not come with test kits so you must use them according to your own estimates.

Safety First

Use only one chemical at a time and make sure all containers and bottles that are not in use are securely closed. Read all the instructions that come with the chemicals very carefully so that you do not have guess at quantities to use.

Once you establish a routine for testing and treating your spa water you will become much more familiar with the processes and more adept at carrying them out. Never become complacent about the use and storage of the chemicals. Always maintain an adequate supply of spa supplies.