The Realities of Owning a Swim Spa or Hot Tub: A Detailed Guide

Hot Tub Water Chemistry and Maintenance

Some questions you might have:

What is the main role of hot tub filters and why is it important to maintain them?
Describe the recommended cleaning frequency for hot tub filters, specifying the methods for weekly and monthly cleaning.
Explain the importance of pH balance in hot tub water, mentioning the ideal pH range and the potential consequences of imbalance.
What are the primary sanitizer options for hot tub water and what are the recommended residual levels for each?
Describe the process of draining and refilling a hot tub every quarter.
List five common contaminants that contribute to cloudy hot tub water.
Describe the process of “shock dosing” a hot tub, explaining its purpose and the different types of shock treatments available.
Besides shocking, what other measures can be taken to clear cloudy hot tub water?
What are the primary causes of foam in hot tub water, and how can it be prevented?
Explain the purpose of shocking a hot tub in relation to sanitiser effectiveness and the removal of chloramines or bromamines.

The answers to your questions

Hot tub filters capture solid and particulate matter to help clear the water. The maintenance of the filters is important for filtration, water clarity, equipment longevity, and chemical effectiveness.
Hot tub filters need to be cleaned weekly with a hose to prevent the build-up of debris. For the monthly cleaning filters need to be soaked in a specialist solution to clear the ingrained contaminants.
Maintaining a pH level of between 7.0 and 7.6 is important for comfort and sanitizer efficiency. Imbalance can lead to skin irritation, equipment damage, scale formation, and reduced sanitizer effectiveness.
Primary sanitisers include chlorine and bromine. Recommended levels are 2-4 mg/l for bromine, 2-4 mg/l for inorganic chlorine, and 3-5 mg/l for organic chlorine.
Quarterly draining and refilling include a system flush to clean pipework, rinsing the shell, vacuuming pipework and jets, refilling through the filter area and adding chlorine or bromine as the tub refills.
Common contaminants include environmental debris (dust, dirt, leaves), organic matter (skin, oils), man-made contaminants (cosmetics, detergents), heavy bather usage and low sanitizer levels.
“Shock dosing” is the process of adding a strong oxidiser to eliminate the contaminants and get the sanitizer back in action. Non-chlorine shock, chlorine granules, bromine granules and single dose sachets are available.
Other methods for clearing cloudy water include adjusting pH and sanitizer levels, cleaning or replacing filters, and using clarifiers to make small particles easier to filter.
Foam is caused by a build up of products and TDS, especially with jets running. Prevent it by showering before use, rinsing suits without detergent, using quality chemicals, regular shock treatments, and aerating the water.
Shocking reactivates the sanitizer by eliminating chloramines and bromamines, byproducts of sanitizer action which decrease its effectiveness and can result in wrong test strip results.

Useful terms

Sanitiser: A chemical, such as chlorine or bromine, that inactivates bacteria and viruses in hot tub water.

pH: A measure of water acidity or alkalinity, with ideal hot tub pH between 7.0 and 7.6.

Total Alkalinity: The water’s ability to stabilise pH levels and maintain balance.

Shock Dosing: Adding concentrated oxidiser to remove contaminants and restore sanitizer efficiency.

Chloramines: When chlorine reacts with ammonia or nitrogen it forms compounds which decrease the effectiveness of sanitiser.

Bromamines: Same as chloramines; formed when bromine reacts with nitrogen compounds.

Clarifier: A substance that binds small particles so that they are easier to filter and the water becomes clearer.

Filter: A pleated fabric component that catches debris and particulates in order to achieve water clarity.

TDS: Total Dissolved Solids, the total dissolved substances in water which cause foam and cloudiness.

Bathing Load: The number of bathers in relation to the water volume and the amount of contaminants and water treatment that is required.

Biofilm: A layer of microorganisms that can form on hot tub surfaces and potentially harbor bacteria.
The Ozonator functions as a device which generates ozone to act as an oxidizer that minimizes chlorine or bromine use.

The UV System employs ultraviolet light technology to kill microorganisms and strengthen sanitizing procedures.

The product functions as a system flush to clean internal hot tub plumbing by clearing out debris before draining and refilling the system.