The most important factor in keeping your hot tub working well and getting the longest possible lifespan out of it is proper maintenance! And a large part of that maintenance is checking and adjusting the chemical balance of the water.

While spas can vary quite a bit and the maintenance for each one will depend upon your usage and local water supply, there are some general tips to keep in mind when you are trying to establish a maintenance schedule for your spa.
Your hot tub will need treating with chemicals fairly often. Most experts recommend checking the water every couple of days or at least twice a week, as well as before each use.
Use a test strip to check the water and compare it with the chart printed on the container. Because it can be difficult to keep all of the chemicals perfectly balanced all of the time, aim for the ideal range with all of them and then focus on perfecting the amount of your chosen sanitizer and the pH level. Maintaining the right level of these two factors will do the most in keeping your spa comfortable for bathers!
When adjusting chemicals, always add them one at a time and wait at least a couple of hours in between in order to properly gauge its effects. This will allow for the chemical to fully penetrate the water of the tub and disperse evenly throughout as well as preventing reactions between chemicals.
Test and adjust your chemicals in alphabetical order: Begin with total alkalinity then adjust bromine/chlorine. Next, check the calcium hardness and finally adjust the pH.
Depending on the sanitizer you choose for your hot tub, the levels will differ. Check the packaging carefully to identify the ideal range. The target levels for the other chemicals are as follows:
Alkalinity | = | 120-180ppm |
Calcium hardness | = | 125-400ppm |
pH | = | 7.2 – 7.8, ideally 7.4 |
The frequency with which you should change the water and chemicals in your hot tub depends almost entirely on how often it is used. Checking the chemical balance frequently is thus essential in order to prevent damage to the tub and discomfort for bathers. In most cases water will need to be changed every 3-6 months, although the use of a good hot tub cover may allow you to stretch that to every 5-8 months. Watch for signs of discomfort such as skin irritations, rashes, or itchy eyes as these will often be the first sign that it is time to refill your spa.