Pool Care & Chemistry
A hot tub is not a small pool
Two hundred gallons at 102 degrees with four people in it is a completely different chemistry problem from four thousand gallons at eighty. Pool products are dosed wrong for it.
Heads up: we earn a commission if you buy through the links on this page, at no extra cost to you. It never decides the ranking — here is how we pick and here is the full disclosure. Prices are checked automatically; last verified October 8, 2026.
Quick picks
Segmented before it is ranked — the right answer depends on which of these you actually are. Tap any row for the full write-up.
The starter kit
Sanitizer, balancers, shock, defoamer and strips in one box, dosed for a few hundred gallons. Pick bromine or chlorine and stay with it.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 | Inflatable Hot Tub Chemical Kit A bromine or chlorine kit packaged for the 200-to-300 gallon world. The reason it exists is that hot tub chemistry moves far faster than pool chemistry and the pool products are dosed wrong for it. | A spa, which is not a small poolOne honest season | 8.0out of 10 |
What you will use most
Strips. On a spa this is not a weekly job — it is every few days, and the kit's strips run out first.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  AquaChek Silver 7-Way Test Strips (100 count) Seven readings in fifteen seconds, including the two that beginners never measure and then fight all summer: total alkalinity and cyanuric acid. | The default first test kitOne honest season | 8.9out of 10 |
What it is going in
The tubs these kits are written for. Both hold a few hundred gallons rather than a few thousand.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  Coleman SaluSpa Inflatable Hot Tub The one most people end up with, and reasonably so. Insulated cover and wall are the specs worth paying for, because everything expensive about owning one of these is heat you paid for and then lost. | The default inflatable hot tubSeveral seasons | 7.6out of 10 | |
| 2 |  Intex PureSpa Inflatable Hot Tub The direct alternative, and the built-in hard water treatment is a genuine point of difference rather than a marketing one if your fill water is hard. | Hard water, and people who already own IntexSeveral seasons | 7.5out of 10 |
The short version
- Bromine is the usual choice because it is more stable than chlorine at hot tub temperatures.
- Bathers per gallon is the real difference. Four people in 250 gallons is an enormous load by pool standards.
- Test every few days, not weekly. A small volume swings fast and the temperature accelerates everything.
- Do not switch sanitizer mid-season without draining. Bromine and chlorine kits are not interchangeable in the same water.
Why pool chemistry does not transfer
Three things change at once when you move from a pool to a spa, and they compound.
Volume. An inflatable hot tub holds a few hundred gallons. Our sizing guide puts even a small frame pool at 1,718 gallons and an 18-foot pool at 6,981. A dose that is a rounding error in a pool is a large correction in a tub.
Bather load per gallon. Our swimmer load guide explains why this is the number that actually predicts sanitizer demand. Four adults in 250 gallons is a ratio a public pool would never approach.
Temperature. Everything is faster at 102°F — sanitizer consumption, bacterial growth, off-gassing. Warm water is the reason a spa needs attention every few days rather than every week.
Bromine or chlorine
| Bromine | Chlorine | |
|---|---|---|
| Stability at 102°F | Better — the main argument | Degrades faster in heat |
| Form | Tablets in a floater | Granules, dosed by hand |
| Smell | Milder | More noticeable in an enclosed tub |
| Reactivation | Shock reactivates spent bromide | Shock is consumed |
| Speed | Slower to act | Faster |
| Cost | Higher per dose | Lower |
| Skin | Some people prefer it, some react to it | Individual |
The heat stability line is why most inflatable hot tub kits are sold as bromine. Our bromine versus chlorine comparison is the full version, and its conclusion for pools — that chlorine wins outdoors because bromine is destroyed by sunlight — reverses in a covered spa where there is no sun to speak of.
What is actually in a starter kit
Current kits are consistent enough that it is worth listing, because it tells you what to replace when the box runs out:
Sanitizer — bromine tablets or chlorine granules. A booster to establish the initial bromide reserve. pH increaser and decreaser. Calcium hardness increaser, which matters more in a spa than a pool because soft water foams and is harder on equipment. Chlorine-free shock, so the tub is usable again quickly. Defoamer. Metal prevent for well water. A floater and test strips.
The strips run out first, and they are the component you should buy more of. Our test strip roundup and test kit roundup both apply — check the strips read bromine if you are on bromine, because not all do.
The two problems every new spa owner gets
Foam. Within a fortnight, reliably. It is soaps, detergents and body products coming off swimwear and skin into a small volume of aerated water. Defoamer is in the kit for that reason and it treats the symptom; the cause is rinsing off before getting in, and washing swimwear without detergent. Our pool foam guide covers the mechanism, which is the same in both.
pH drift upward. Aeration drives off carbon dioxide, which raises pH, and a spa is aerated continuously by its own jets. That is not a fault — it is physics, and it is why a spa needs pH decreaser far more often than a pool does. Our pH and alkalinity guide covers the order to correct in, and it does not change: alkalinity first, then pH.
The routine, honestly
Test every two or three days, and after any session with several people in it. Keep the sanitizer in range, correct pH when it drifts, shock weekly or after heavy use, and change the water every few weeks to a few months depending on use.
That last item is the one people underestimate, and it is the honest cost of a spa: our hot tub versus pool comparison notes that a pool is filled once a season and a tub several times a year. Small volumes are cheap to refill and impossible to rescue.
What we are scoring
We have not tested these and do not claim to. The scores reflect published contents and dosing — sanitizer type, what balancers are included and what the kit expects you to test — against an inflatable hot tub of a few hundred gallons. Our methodology page explains how our scoring works.
The picks, in full
Scores are our own reading of published specifications. They are not test results — we have not tested these products and we do not claim to.
Pick #1 · A spa, which is not a small pool
Inflatable Hot Tub Chemical Kit
Various
A bromine or chlorine kit packaged for the 200-to-300 gallon world. The reason it exists is that hot tub chemistry moves far faster than pool chemistry and the pool products are dosed wrong for it.
#ad how this is funded · price as of October 8, 2026
Key specs
- Sanitizer
- Bromine tablets or chlorine granules — pick one
- Typically includes
- Sanitizer, booster, pH up and down, calcium increaser
- Also includes
- Chlorine-free shock, defoamer, metal prevent, test strips
- Delivery
- A floater is usually in the box for bromine kits
- Volume
- Dosed for a few hundred gallons, not a few thousand
- Testing
- Strips included; test far more often than a pool
How it scoresour reading of published specs, not a test result
- Effectiveness
- 8.5
- Ease
- 9.0
- Water impact
- 7.5
- Cost per season
- 7.0
- Value
- 8.0
Overall 8.0 / 10
What works
- Dosed for spa volumes, so you are not measuring fractions of a pool scoop
- Bromine is more stable than chlorine at hot tub temperatures
- Chlorine-free shock means the tub is usable again quickly after treatment
- Defoamer is in the box, which every new spa owner needs within two weeks
What doesn't
- Small volume means chemistry swings fast and needs testing every few days
- Bromine and chlorine kits are not interchangeable mid-season without a drain
- A starter kit is a season at most on a well-used tub
- Metal prevent and calcium increaser are only needed on some water supplies
Skip it if: Being used on a pool. The dosing is wrong by an order of magnitude and you will spend far more than buying pool chemistry.
What it costs to run: Cheaper per unit than buying the eight components separately, and the components you do not need are the waste. On a tub you refill every few weeks, this is a recurring line, not a one-off.
One honest season: The cheapest setup that genuinely works for a season of real swimming. Nothing spare, nothing missing.
Specs from: AquaDoc inflatable hot tub chemical kit with bromine — Amazon listing
Pick #2 · The default first test kit
AquaChek Silver 7-Way Test Strips (100 count)
AquaChek
Seven readings in fifteen seconds, including the two that beginners never measure and then fight all summer: total alkalinity and cyanuric acid.
#ad how this is funded · price as of October 8, 2026
Key specs
- Tests
- Free chlorine, total chlorine, bromine, pH, total alkalinity, total hardness, cyanuric acid
- Free chlorine range
- 0-20 ppm
- pH range
- 6.2-8.4
- Total alkalinity range
- 0-240 ppm
- Cyanuric acid range
- 0-300 ppm
- Read time
- 15 seconds
- Count
- 100 strips
How it scoresour reading of published specs, not a test result
- Accuracy
- 7.0
- Ease
- 9.5
- Coverage
- 9.5
- Cost per use
- 9.0
- Value
- 9.2
Overall 8.9 / 10
What works
- Covers cyanuric acid, which most cheap strips omit and which is the reason chlorine stops working in a stabilized pool
- pH range spans 6.2-8.4, comfortably bracketing the CDC's recommended 7.0-7.8
- 15 seconds and a color chart printed on the bottle — no separate booklet to lose
- 100 strips is a full season of twice-weekly testing with room to spare
What doesn't
- Strips are a comparison against a printed color chart, so they are directional rather than precise
- Reading them in bright sun is harder than it should be
- The bottle must be kept sealed and dry or the strips degrade quietly
Skip it if: Fine adjustment. If you are chasing a stubborn problem and need a number rather than a color band, a liquid reagent kit is the tool.
What it costs to run: 100 strips at twice-weekly testing covers roughly two seasons for one pool. The real saving is upstream: knowing your alkalinity stops you buying pH adjuster you did not need.
One honest season: The cheapest setup that genuinely works for a season of real swimming. Nothing spare, nothing missing.
Specs from: CDC — home pool and hot tub water treatment and testing
Pick #3 · The default inflatable hot tub
Coleman SaluSpa Inflatable Hot Tub
Coleman (Bestway)
The one most people end up with, and reasonably so. Insulated cover and wall are the specs worth paying for, because everything expensive about owning one of these is heat you paid for and then lost.
Key specs
- Capacity
- 4 to 6 people, depending on SKU
- Size
- 71in or 77in round x 28in, per model
- Jets
- 140 AirJets on current models
- Cover
- EnergySense insulated cover included
- Cold weather
- Freeze Shield on current models
- Running cost
- Not published — depends on your rate and ambient temperature
How it scoresour reading of published specs, not a test result
- Build
- 7.5
- Setup
- 9.0
- Upkeep
- 6.5
- Running cost
- 5.5
- Value
- 8.0
Overall 7.6 / 10
What works
- Insulated cover and wall are the features that actually govern the running cost
- No installation, no permit conversation, no groundwork beyond a level base
- Packs away, which matters if the yard has one usable corner
- Widely stocked, so replacement filters and parts are easy to find
What doesn't
- Air jets, not water jets — this is bubbles rather than massage, and people expect the latter
- Heating is slow by design; you plan around it rather than deciding on the day
- Filter cartridges are a frequent consumable at spa bather loads
- Vinyl in constant hot water ages faster than the same vinyl in a pool
Skip it if: Anyone expecting hydrotherapy jets. It is a warm bubbling tub, and that is a different product from a hard-shell spa.
What it costs to run: The purchase is the small number. A hot tub is heated 24/7 rather than seasonally, so the electricity is the real commitment and it is entirely a function of your rate, your cover discipline and your climate. Nobody publishes a national figure and we will not invent one.
Several seasons: Buy-once. Built and warranted to come back out of the box for a few years, if you store it properly.
Specs from: Coleman SaluSpa — current Amazon listing and published specifications
Pick #4 · Hard water, and people who already own Intex
Intex PureSpa Inflatable Hot Tub
Intex
The direct alternative, and the built-in hard water treatment is a genuine point of difference rather than a marketing one if your fill water is hard.
#ad how this is funded · price as of October 8, 2026
Key specs
- Capacity
- 4 people (28429EP)
- Size
- 77in round x 28in
- Water treatment
- Built-in hard water treatment system
- Included
- Energy-efficient spa cover, 2 headrests, LED light
- Jets
- Bubble massage — air, not water jets
- Running cost
- Not published
How it scoresour reading of published specs, not a test result
- Build
- 7.5
- Setup
- 9.0
- Upkeep
- 6.5
- Running cost
- 5.5
- Value
- 7.8
Overall 7.5 / 10
What works
- Built-in hard water treatment is a real advantage on hard fill water
- Insulated cover included rather than sold separately
- Shares the Intex accessory ecosystem if you already own an Intex pool
- Headrests and light included, which are usually add-ons elsewhere
What doesn't
- Air bubbles rather than water jets, same as the category
- Four people is a genuine four, not an optimistic one
- Cartridges need changing often at spa temperatures and bather loads
- Wattage is not published, so the running cost cannot be computed before purchase
Skip it if: Cold-climate winter use without serious attention to the cover and the ground under it. These are insulated, not immune.
What it costs to run: Same shape as the rest of the category: the electricity dwarfs the purchase over a year. The one lever you control is whether the cover goes back on every single time.
Several seasons: Buy-once. Built and warranted to come back out of the box for a few years, if you store it properly.
Specs from: Intex PureSpa 28429EP — current Amazon listing and published specifications
Questions people actually ask
Should I use bromine or chlorine in an inflatable hot tub?
Can I use pool chemicals in a hot tub?
How often should I test hot tub water?
Why does my hot tub foam?
Sources
Read next
- Pool care, from someone who assumes you have never done thisThe weekly routine, the four numbers that matter, and the fix for the week the water turns.
- Bromine or chlorine: sunlight settles itWhy bromine works in a covered hot tub and struggles in an open pool, what it costs, and when it is still the right answer.
- Pool test kits, and when you need a number rather than a colorReagent kits and digital testers compared against strips, with the specific situations where each one earns its place.
- The best pool test stripsTest strips compared on parameter coverage - specifically whether they read cyanuric acid, which most cheap strips omit.
- Bather load: the variable that explains your worst weeksWhy gallons per swimmer is the number that matters, what a busy afternoon costs you in chlorine, and the routine that absorbs it.
- Foam on the water is a report on what went inThe four things that make a pool foam, how to tell them apart, and why anti-foam products hide the cause rather than fixing it.
- Inflatable hot tubs, judged on the bill rather than the bubblesThe two inflatable hot tubs worth shortlisting, compared on insulation and cover rather than jet count, plus the running cost nobody publishes.
- The pool is seasonal. The hot tub is a standing charge.Why an inflatable hot tub and an above-ground pool have opposite running-cost profiles, and which one suits which household.
- pH and alkalinity, and why yours will not stay putWhy pH drifts, what total alkalinity actually does, and the order of operations that turns a season of chasing into one adjustment.