If we use our hot tub almost everyday, will we need to change the water more often?


It is hard to say just what constitutes “frequent” use of a hot tub.
Rule of Thumb: if you frequently use your hot tub, you should replace the water more often. In addition to the “Rule of Thumb” mentioned above, we suggest using our “Units of Usage” formula. This formula will help you calculate how much exposure your hot tub’s water has had to bathers & their body chemistry. We recommend you change your water after every 75 Units of Usage (uu).
The formula is easy to calculate & is based on the following equation:
1 person using a hot tub for 20 minutes = 1 uu
The rest is simple math: divide 75uu (without ozonation) or 125uu (with ozonation) by your weekly uu level to determine the number of weeks (rounded down to nearest whole week) between drainings of your hot tub. The following example should help you determine your own uu level on a weekly basis.

2 people using a hot tub for 20 minutes, 3 times per week Weekly uu: 2 x 1 uu x 3= 6uu/week Weeks before draining: 75uu/6uu = 12.5 weeks
While this formula is a useful measuring tool, bear in mind that people perspire at different levels and that your water’s chemistry is just as unique as you are. If you are using an ozonator to help sanitize your water you may be able to reach a level between 90 and 125uu before changing your water. By the way, if a dog or cat should find its way into your tub, you may want to drain the water immediately. Unfortunately, pets produce bacteria at a rate approximately 50 times faster than humans.

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