The truth about owning a swim spa or hot tub: Key terms and questions answered

What you can learn from this article:

1. What essential electrical considerations should be addressed before installing a hot tub?
2. Why is it crucial to have a site survey conducted before a hot tub is delivered?
3. Explain the importance of calcium hardness in hot tub water and the recommended levels.
4. What are the recommended daily checks for hot tub water, and why are they important?
5. Detail the recommended weekly checks for hot tub water maintenance.
6. Outline the steps for cleaning hot tub filters and the recommended frequency.
7. What are the common causes of cloudy hot tub water, and how can it be remedied?
8. Describe the purpose of “shocking” a hot tub and the recommended frequency.

Answer Key

1. Hot tubs require a dedicated, correctly-sized fused spur, SWA cable wired directly to the consumer unit, and RCD protection. All electrical work must be conducted by a competent person according to Part P Building Regulations.
2. A site survey confirms that your home can accommodate the hot tub, considering factors like access, foundation suitability, and electrical supply.
3. Calcium hardness (200-400 mg/l) contributes to water quality and equipment longevity. High levels can cause scaling, while low levels can lead to foaming and corrosion.
4. Daily checks involve testing sanitizer (chlorine or bromine) and pH levels to ensure water safety and prevent skin/eye irritation. Sanitizer levels should be between 2-4 mg/l for bromine and inorganic chlorine, 3-5 mg/l for organic chlorine. pH should be maintained between 7.0-7.6.
5. Weekly checks include testing total alkalinity (ideally 125-150 mg/l, minimum 80 mg/l) to stabilize pH, adding anti-scale treatment in hard water areas, visually inspecting for debris, and cleaning the waterline.
6. Filters should be rinsed weekly with a garden hose and a filter cleaning product used monthly to remove oils. Replace filters annually or every two years if rotating two sets.
7. Cloudy water is often caused by environmental debris, organic matter, or insufficient sanitizer. Remedy involves balancing water chemistry, shock dosing, cleaning filters, and using a clarifier.
8. “Shocking” involves oxidizing impurities, killing bacteria, and reactivating sanitizer. It’s recommended weekly and after heavy usage to maintain water clarity and hygiene.

Key Terms you should know:

• Calcium Hardness: The amount of dissolved calcium in water, influencing water quality and equipment longevity.
• Chloramines/Bromamines: Byproducts of chlorine/bromine breakdown, indicating reduced sanitizer effectiveness.
• Clarifier: A chemical treatment that binds small particles, making them filterable and improving water clarity.
• Consumer Unit: The main distribution board for electrical circuits in a property.
• Fused Spur: A dedicated electrical circuit with a fuse for a specific appliance, like a hot tub.
• RCD: Residual Current Device – a safety device that detects electrical leakage and interrupts the circuit.
• Sanitizer: Chlorine or bromine-based chemicals that kill bacteria and maintain water hygiene.
• Shock Dosing: Oxidizing the water to break down impurities, kill bacteria, and reactivate sanitizer.
• Site Survey: An assessment of a location to determine its suitability for hot tub installation.
• SWA Cable: Steel Wire Armoured Cable – a robust electrical cable suitable for outdoor installations.
• Total Alkalinity (TA): The water’s ability to resist pH changes, contributing to water stability.