Essential hot tub chemicals

Clear water, every week — without the guesswork.

Everything you need to keep your hot tub clean, balanced and sparkling — sanitisers, pH and alkalinity balancers, weekly shock, clarifier, scale inhibitor and defoamer — all in one place. Pair any bottle with our free dosing app: tell it your spa volume and current test readings, and it tells you exactly what to add. Fits any brand of hot tub, not just ours. UK stock, fast despatch.

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A weekly routine that's hard to get wrong

Hot tub water care doesn't need to be intimidating. A sanitiser, balanced pH and alkalinity, a weekly shock, and a clarifier when needed — that's 90% of the job. Here's how we make that easy.

  • Free dosing app — no more guesswork

    Type in your spa volume and your test-strip readings; the app tells you exactly how much of each product to add. No maths, no overdosing, no wasted chemicals. Included free with every order.

  • Complete water-care range in one place

    Chlorine or bromine sanitisers, pH down, alkalinity booster, non-chlorine shock, clarifier/flocculant, stain & scale inhibitor, defoamer and test strips — everything you need in a weekly routine, from one supplier.

  • Starter & complete kits for easy setup

    New to hot tub ownership? Our Starter Kit bundles the essentials at a sharp price; our Complete Kit covers you for a full season. Both include the free app so you know exactly what to do, and when.

  • UK stock, fast despatch

    Every chemical listed here is stocked in our UK warehouse. Order by early afternoon on a working day and your chemicals typically ship the same day — so you're not waiting a week for a missing bottle of pH down.

Essential Chemicals Buying Advice

Use this collection to compare specifications, delivery options, and aftercare before you buy. Contact our UK support team for help choosing the right model for your space and budget.

26 products

Essential Chemicals: UK Buying Guide

This collection is part of the Canadian Spa Company UK range of hot tubs, swim spas, saunas and spa essentials. Compare options by fit for your space, running costs, insulation, warranty and ongoing maintenance requirements to make a better long-term choice.

If you need help choosing the right model or part, our support team can guide you on compatibility, delivery and aftercare.

Why it matters

What balanced water actually gets you

Clean water isn't about chasing perfect test strips — it's about a spa that feels good to use and lasts a long time. Here's what a proper weekly routine delivers.

  • Crystal-clear water week after week

    Balanced pH and sanitiser keep water visibly clear, not cloudy — the visual cue that your spa is actually healthy to sit in.

  • Kinder to skin and eyes

    Unbalanced water is what makes hot tubs sting your eyes and dry out your skin. Correct pH (7.2–7.6) and correct sanitiser level fix both.

  • Protects your spa from scale and stains

    Stain & scale inhibitor stops limescale building up in your pipework, pumps and heater element — the single most common cause of premature spa failure in hard-water areas.

  • Weekly shock resets your water

    A weekly dose of non-chlorine shock burns off organics — sweat, body oils, dead skin — that sanitiser alone can't handle. The difference in water quality is obvious from the first session.

  • Small bottles, long run-time

    A 500g tub of granules or a 1kg shock bottle covers most owners for months. Hot tub chemistry is a surprisingly low-cost ongoing spend once you're set up.

  • Works on any brand of spa

    Spa chemistry is universal — our chemicals work just as well on Jacuzzi, Hotspring, Arctic, Aegean, Clearwater and every other hard-shell hot tub as they do on Canadian Spa.

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Common questions

Hot tub chemical FAQ

I'm brand new to hot tubs — where do I start?

Start with our Starter Hot Tub Chemical Kit. It includes a sanitiser, pH down, alkalinity booster, test strips and the free dosing app. Once you're comfortable and know your weekly rhythm, move on to individual refills or our Complete Chemical Kit for a full season.

The app walks you through your first dose step by step, and thereafter your weekly routine takes 5 minutes.

Bromine or chlorine — which should I use?

Chlorine is cheaper, works faster, and has a stronger smell. Best if you use your hot tub most days.

Bromine is gentler on skin and eyes, more stable at hot-tub temperatures, and almost odourless. Best if you share the spa with young children or anyone with sensitive skin, or if you use it less frequently.

Don't mix the two in the same water — empty, clean and refill your spa when switching between them.

How often should I test my water?

Test at least twice a week, and always before you get in if you haven't used the spa for more than a couple of days. Aim for pH 7.2–7.6, alkalinity 80–120 ppm, and sanitiser (chlorine 3–5 ppm OR bromine 3–5 ppm). Our test strips read all three in 15 seconds; enter the numbers into the free app and it does the maths.

Do your chemicals work with non-Canadian Spa hot tubs?

Yes — all our chemicals are standard spa chemistry and work on any hard-shell hot tub (Jacuzzi, Hotspring, Arctic, Aegean, Clearwater, Beachcomber, Marquis, etc.) and most inflatable spas too. The app's dose calculator asks for your spa volume in litres, so brand doesn't matter.

What is shock and when do I use it?

Shock is a concentrated oxidiser that burns off the body oils, sweat and dead skin cells that build up in spa water faster than sanitiser can handle them. Dose weekly as a rule, and any time after heavy use (a party, more than 2–3 bathers), after rain, or if the water starts to look cloudy. Our Non-Chlorine Spa Shock is the most common choice — it doesn't spike chlorine and is safe to bathe again within 15 minutes.

My water is foaming or cloudy — what do I do?

Foaming is usually caused by body oils, sunscreen, hair products and detergent residues (from swimwear washed with fabric softener). Add a dose of Foam Free to knock it down immediately, then shock the water. Shower before you get in and rinse swimwear in clean water to prevent it returning.

Cloudy water is usually an imbalance (test pH and alkalinity first) or fine particulate that the filter isn't catching. A dose of Spa Clear (clarifier/flocculant) clumps the particles together so the filter can remove them — overnight filtration will clear most cases.

How long do these chemicals last once opened?

Stored cool, dry and sealed: chlorine and bromine granules/tablets last around 2 years; pH down and alkalinity booster effectively indefinite; liquid products (clarifier, defoamer, scale inhibitor) roughly 2 years; test strips 12–18 months once opened (expiry printed on the tub). Keep the lids tight and don't store in a damp outdoor cupboard — moisture degrades granular chlorine fastest.

Any safety basics I should know?

Always add chemical to water, never water to chemical. Never mix different chemicals together in the same scoop or bottle. Store out of reach of children and pets. Wait at least 15 minutes after dosing before bathing, with the cover off and pumps running on low, so the chemical fully circulates. And always test first — never dose blind.

UK buying guide

Hot Tub Chemicals UK — buying guide

Hot tub water care is simpler than most new owners expect. Keep the sanitiser level correct, keep pH and alkalinity inside the right band, shock weekly, and dose a clarifier or scale inhibitor when needed. That's it. The reason most people find it confusing is that they buy random bottles from random suppliers, with no dosing guidance. Our Essential Chemicals range is built to make the weekly routine obvious — one supplier, UK stocked, and a free dosing app that tells you exactly what to add and how much.

The weekly routine — in plain English

  • Daily (30 seconds): glance at the water. Cloudy? Test.
  • Twice a week (3 minutes): dip a test strip, read pH / alkalinity / sanitiser, adjust if needed.
  • Once a week (5 minutes): dose a non-chlorine shock, rinse the filter cartridge under a tap.
  • Every few months: soak the filter in filter cleaner overnight, replace any depleted chemicals, refresh test strips once expired.

Your target readings

  • pH: 7.2–7.6 (slightly alkaline, skin-neutral)
  • Total alkalinity: 80–120 ppm (buffer that stops pH swinging)
  • Free chlorine: 3–5 ppm (if chlorine-sanitised)
  • Total bromine: 3–5 ppm (if bromine-sanitised)

Chlorine vs bromine — picking your sanitiser

Chlorine is cheaper, acts faster and is the default for daily-use spas. Bromine is gentler on skin and eyes, more stable at hot-tub temperatures, and a better choice for sensitive-skin users, young children or less-frequent use. Both are equally effective at killing bacteria; don't try to mix them in the same water.

How the free dosing app works

Every chemical order includes free access to our hot tub dosing app. Enter your spa volume (litres) once, then each time you test the water you type the pH, alkalinity and sanitiser reading — the app calculates the exact dose of each product to bring the numbers back into range. It logs your readings over time so you can spot patterns (e.g. pH always drifts down after a week of heavy use).

Works with any brand of hot tub

Our chemicals are standard-chemistry spa products and work on any hard-shell hot tub brand — Canadian Spa, Jacuzzi, Hotspring, Arctic Spas, Aegean, Clearwater, Marquis, Beachcomber and others — plus most inflatable spas (Lay-Z-Spa, Intex). Only the spa volume changes the dose; brand is irrelevant.

UK stock, fast despatch

Every product on this page is held in our UK warehouse. Orders placed by early afternoon on working days typically despatch the same day; kerb-side delivery to UK mainland is included on most bottles. No waiting on overseas shipping, no surprise customs charges.

Frequently asked

Which hot tub chemical kit should I buy UK?

For brand-new owners, the Starter Hot Tub Chemical Kit is the right place to begin — it includes the sanitiser, balancers and test strips you need for your first few weeks, plus free access to the dosing app. Step up to the Complete Chemical Kit when you're ready for a full season's supply in one box.

How often do I need to add chemicals to my hot tub?

Sanitiser top-up and weekly shock are the two fixed habits. Test twice a week; adjust pH or alkalinity only when a reading is outside range. Clarifier and defoamer are dosed as-needed rather than weekly. A typical owner actively doses chemicals around once a week, with a 3-minute test between.

Can I use Canadian Spa Company chemicals in a Lay-Z-Spa or other inflatable?

Yes — spa chemistry is universal. Our granular chlorine, bromine tabs, pH down, alkalinity booster, shock, clarifier and defoamer all work in inflatable spas as well as hard-shell hot tubs. The only thing that changes between spa types is the volume (litres) and therefore the dose size — the free app handles that for you.

How long after shocking the water can I get back in?

Non-chlorine shock: around 15 minutes with the pumps running on low and the cover off. Chlorine-based shock (not included in our core range): test the sanitiser level has dropped back below 10 ppm before bathing — typically 30–60 minutes depending on spa volume and dose.

Do I need different chemicals in winter?

No — the chemical routine stays the same year-round. What changes is usage patterns: in winter you might shower less often before getting in, and the water warms and cools through bigger temperature swings, so shock a little more often if you're bathing on cold days. The cover insulation matters far more for heat loss than chemistry does.