Spa Water Manteinance Guide
Crystal-clear water,
three products.
Forget the formulas and the shelf full of "special products". A spa is not a pool — and after installing hundreds of them we've boiled water care down to three things: a calcium reducer, a pH adjuster, and good old dichlor. A tablespoon at a time.
A spa is not a pool
15–60× less water · always covered · sun and bugs locked out
Pool HIGH MAINTENANCE
Spa EASY
Sanitisers, ranked
What we've tested · what we recommend · what to skip
DichlorPOWDER · DOSED
The right amount, the right time. A tablespoon after each use kills the bacteria the bathers brought in — nothing more.
BromineTABLET · SLOW
Sold as smell-free — it isn't. Tablets dissolve over days, so casual users end up over-dosed. And it banks: too much never disappears.
OzoneO₃ · GENERATOR
Made on board from air. Sanitises continuously while filtering — cuts your chlorine need by up to 70%. Still needs a small chemical top-up.
UVGERMICIDAL · LAMP
High-intensity UV scrambles the DNA of algae, bacteria, viruses, cysts and protozoa. Same tech that purifies tap water — perfectly safe.
SaltELECTROLYTIC · CELL
A pinch of salt — half as salty as a tear — is split by electrolysis into chlorine or bromine on demand. You still get sanitiser, just generated in-cell.
Keep these four in the green
Glance · adjust · soak. That's it.
Target ranges
What you actually need
- Dichlor · powder — a tablespoon after usereplaces: chlorine tablets, shock, multi-action
- pH adjuster — push above or below as neededcheap · long-lasting
- Calcium reducer — only when your tap water is hardmost of the Costa: yes
- Algicide, clarifier, "shock plus", scale-blocker, foam-out…— skip the upsell shelf
What to do, and when
If you keep the cover on, the calendar is short
1 tbsp dichlor
Sanitises the bacteria the bathers just brought in. Cover & walk away.
EVERY SOAKRinse the filter
Hose down the pleats — or pop it in the dishwasher (not too hot). Clogged filter = dirty water + dead heater.
2 MINDeep-clean filter
Soak in filter-cleaning liquid. Many owners keep a second filter on hand for swap-and-clean.
SPARE FILTERDrain & refill
Used 3–6× a week? Swap the water. Salts and acids slowly build up in any chlorinated system.
90 DAYSUp to 1 month
Sanitise well, close the cover, leave it. Covered water stays clean — same logic as a water tank.
TRAVEL OKThe things people get wrong
Heard at every showroom · debunked once
Chlorine smells, so it's bad for you.
The smell isn't chlorine — it's chloramines (chlorine bound to ammonia and nitrogen). They're 60–80× weaker. Counter-intuitively, the fix is to add more chlorine to break them apart.
SHOCK · 10 PPM · 4 HBromine is gentler and odour-free.
Both untrue. The smell is just different, and tablets keep releasing whether you use the spa or not — so casual users live in a permanent overdose. Excess bromine never dissipates.
DICHLOR · DOSED · CLEARYou should keep it like a pool.
You shouldn't. A spa is closed, tiny, and only contaminated by bathers. Run your spa like a pool and you'll over-chlorinate, irritate skin, and burn through chemicals you don't need.
COVER ON · 1 TBSP · DONENeed the full guide? It's free.
Download the Water Maintenance PDF, or grab the Ozone, UV and Salt-system briefs from our resources page.
