Most hot tub repairs we attend are caused by poor maintenance, not faulty equipment. A £15 filter left unchanged becomes a £400 pump replacement. A missed water test becomes a £200 shell resurfacing job. Here are the five mistakes we see most often — and what to do instead.
1. Not Testing the Water Weekly
This is the most common mistake and the most expensive over time. Out-of-range water doesn’t just feel uncomfortable — it actively damages your equipment.
| What goes wrong | pH too low (acidic) | pH too high (alkaline) |
|---|---|---|
| Equipment | Corrodes heater element, pump seals | Scale buildup clogs jets, heater |
| Shell | Etches and dulls acrylic surface | Cloudy water, biofilm growth |
| Users | Skin and eye irritation | Skin irritation, reduced sanitiser effectiveness |
| Repair cost | £150-400 (heater/pump seal) | £100-300 (descaling, jet replacement) |
The fix: Test weekly with strips or a digital tester. Target pH 7.2-7.6, alkalinity 80-120 ppm, free chlorine 3-5 ppm. Takes 60 seconds.
2. Ignoring the Filters
Your filter cartridge is the single hardest-working component in the tub. It runs 24/7, trapping debris, oils, and bacteria. When it clogs, your pump has to work harder — drawing more electricity and wearing out faster.
How often to clean: Rinse with a hose every 2-4 weeks. Deep soak in filter cleaner every month. Replace entirely every 12-18 months.
What a blocked filter costs you:
- 15-30% higher electricity bills (pump working harder)
- Pump lifespan reduced from 7-10 years to 3-5 years
- Replacement pump: £200-500 installed
A replacement filter cartridge costs £15-40. The maths speaks for itself.
3. Not Draining Every 3-4 Months
No amount of chemical balancing keeps the same water fresh indefinitely. Total dissolved solids (TDS) accumulate — skin cells, body oils, cosmetics, sunscreen — and eventually the water becomes unmanageable. You’ll use more chemicals trying to balance it, and the water will still look and feel off.
The rule: Drain completely, wipe down the shell with a non-abrasive cleaner, rinse, and refill every 3-4 months. This is also the best time to inspect jets and plumbing for early signs of leaks.
4. Neglecting the Cover
Your hot tub cover isn’t glamorous, but it’s responsible for up to 75% of your tub’s heat retention. A worn, waterlogged cover is essentially a sponge sitting on top of your tub — it stops insulating and starts costing you money.
| Cover condition | Estimated annual energy cost |
|---|---|
| Good cover (dry, intact) | £300-500 |
| Worn cover (heavy, waterlogged) | £600-900 |
| No cover | £1,000-1,500+ |
Maintain it: Clean monthly with mild soap. Apply UV protectant spray twice a year. If the cover is heavy when you lift it (waterlogged foam), it’s time for a new one — they’re £150-300 and pay for themselves within a year in energy savings.
5. Skipping the Annual Service
Everything might seem fine. The water’s warm, the jets are firing, the lights work. But underneath, problems can develop silently — corroded electrical connections, slow leaks into the foam insulation, biofilm buildup in the pipework.
An annual service catches these before they become expensive failures. We check:
- Pump and heater operation and current draw
- Electrical connections and earth bonding
- Jet and valve function
- Pipework for leaks or biofilm
- Control board diagnostics
- Cover condition
Our maintenance packages start at £70 for a basic chemical starter kit, up to £330 for the Ultimate package (full pipework flush, filter replacement, cover treatment, and comprehensive health check).
The Bottom Line
A well-maintained hot tub costs £300-500 per year to run. A neglected one costs £600-1,500 — and that’s before you factor in repair bills. Spending 10 minutes a week on basic maintenance saves hundreds of pounds a year.
If your tub needs attention, get in touch. Diagnostic visits start at £75, and we carry common parts on the van for same-day fixes. Call 07405 112338 or request a quote online.