Quick Answer: It depends on who made your tub. Intex and Bestway build their inflatables around chlorine tablets: Intex’s PureSpa manual says to put 1 tablet under 1 inch across in its floating dispenser and take it out while the spa is in use, and Bestway’s SaluSpa insert says its dispenser is “for use with chemical tablets only.” Softub and 9 of the 10 hard-shell spa brands whose manuals we read say no: Hot Spring, Jacuzzi, Bullfrog, Cal Spas, Master Spas, Marquis and others forbid trichlor tablets or exclude the damage from warranty, and Softub says a floater with tablets voids its warranty. Wherever tablets are allowed, use one small tablet at a time, because by our math a single 1-inch trichlor tablet (about 17 g) holds enough chlorine to push a 290-gallon tub to roughly 14 ppm, against the 2 to 4 ppm Intex and Bestway target.
Published November 5, 2026. Water care rules come from each maker’s own owner’s manuals and support pages, read November 5, 2026. Product prices were checked the same day on the online store of Leisure Time Inc., an Idaho hot tub dealer. We don’t test hot tubs or chemicals ourselves. Tablet dose and cyanuric acid figures are our math from the published chemistry.
“Chlorine tablets” usually means the 1-inch tablets, 3-inch pucks or sticks sold for pools, and almost all of them are trichlor (trichloroisocyanuric acid). They’re made to dissolve slowly in thousands of gallons of cool water. A hot tub holds a few hundred gallons of 100°F-plus water churned by jets or bubbles, so the same tablet dissolves faster into much less water. That’s why tub makers split into two camps: inflatable brands that supply a tiny one-tablet floater, and spa brands that ban tablets and floaters entirely.
Chlorine tablets for hot tubs by the numbers
- 1 tablet, under 1 inch: Intex’s instruction for its PureSpa floating dispenser, in both its 2025 Greywood Deluxe and Sahara Tan manuals. The dispenser comes out of the water while the spa is in use.
- 9 of 10: the acrylic and rotomolded spa brands whose current manuals we read that forbid trichlor or chlorine tablets, or exclude tablet damage from the warranty: Hot Spring, Jacuzzi, Sundance, Bullfrog, Cal Spas, Master Spas, Marquis, LifeSmart and Watkins’ Aquaterra. AquaRest’s manual doesn’t mention tablets.
- 2 to 4 ppm free chlorine: the target in Intex’s and Bestway’s US manuals. Intex lists 2 ppm as the minimum and 5 ppm as the maximum. MSpa and Watkins’ Aquaterra manual use 3 to 5 ppm, and the CDC’s home hot tub guidance says at least 3 ppm.
- About 14 ppm from one tablet: our estimate for a single 1-inch trichlor tablet fully dissolved in a 290-gallon tub, the size of Intex’s 6-person PureSpa. We used about 17 g per tablet (BioGuard’s figure of roughly 27 one-inch tablets per 16 oz) and 90% available chlorine. In a 210-gallon tub it’s about 19 ppm.
- 0.6 vs. 0.9 ppm: the cyanuric acid (CYA) left behind for every 1 ppm of chlorine from trichlor vs. dichlor, per Trouble Free Pool’s chemistry glossary. The granular “spa” chlorine actually adds about 50% more stabilizer per dose. Bestway’s Lay-Z-Spa manual targets 30 to 50 ppm CYA.
- $9.80 vs. $18.60 a pound: Leisure Time Spa 56 dichlor granules vs. GLB Small 1-inch trichlor tablets, both in 5 lb tubs, at the same dealer on November 5, 2026.
What each hot tub maker says about chlorine tablets
| Maker and tub type | Chlorine tablets? | What the manual says | Free chlorine target |
|---|---|---|---|
| Intex PureSpa (inflatable) | Yes, in the included floater | "Add 1 tablet into the dispenser," tablet under 1 in (2.5 cm); remove the dispenser when the spa is in use; never let undissolved chlorine touch the tub | 2–4 ppm (min 2, max 5) |
| Bestway SaluSpa, US (inflatable) | Yes, tablets only in the dispenser | "This is supplied for use with chemical tablets only. Do not use granules"; remove the dispenser when the spa is in use | 2–4 ppm, pH 7.4–7.6 |
| Bestway Lay-Z-Spa, UK (inflatable) | Yes, in the ChemConnect dispenser | Tablets only in the dispenser; don't throw tablets, granules or liquid directly in the water, or they settle and discolor the PVC | 2.0–4.0 ppm, CYA 30–50 ppm |
| MSpa (inflatable) | Yes, 1-inch tablets in the dispenser | "This dispenser only applies to 1" tablet"; don't use concentrated chlorine | 3–5 ppm |
| Softub (foam and vinyl) | No | "DO NOT USE FLOATERS OR TABLETS"; a floating dispenser with tablets voids the warranty; sodium dichlor is "the only recommended sanitizer" | Not stated in the passages we read |
| Watkins Aquaterra, sold at Costco (rotomolded) | No trichlor | "Never use a sodium trichlor tablet in any form even with a floater"; granular sodium dichlor "highly recommended" | 3.0–5.0 ppm |
| Hot Spring (Watkins), acrylic | No | "DO NOT use tri-chlor chlorine" or any compressed bromine or chlorine; Watkins doesn't recommend any floating dispenser, and floater damage is "specifically not covered" by the warranty | See manual |
| Jacuzzi and Sundance, acrylic | No trichlor | "Never add chlorine tablets (trichlor) or acid to your hot tub for any reason," which may void the warranty; Sundance allows bromine tablets in its built-in Brominator and granular dichlor | See manual |
| Bullfrog, acrylic | No trichlor | "Trichlor chlorine tablets should never be used in a portable spa"; use voids the warranty; bromine and dichlor tablets only with a proper feeder | See manual |
| Cal Spas, acrylic | No trichlor | "DO NOT USE Trichlor"; it dissolves too fast in hot water and "will void your warranty"; warns floaters can blister the shell | See manual |
| Master Spas, acrylic | No | Sodium dichlor is the only approved chlorine; damage from "tri-chlor" type chlorines or calcium hypochlorite is excluded from warranty | See manual |
| Marquis, acrylic | No trichlor | Trichlor damage "is not covered under warranty"; recommends FROG floating cartridges but no other floating dispensers | See manual |
| LifeSmart, rotomolded | No | "Never use compressed sanitizers even with a floater"; granular sodium dichlor highly recommended | See manual |
| AquaRest, rotomolded | Not addressed | No tablet wording; "Damage due to improper chemistry will void warranty" | See manual |
Sources: Intex PureSpa owner’s manuals (Greywood Deluxe SB-HWF10-1 and Sahara Tan SB-HS10-1, both 2025) and intexcorp.com’s spa water maintenance page; Bestway’s SaluSpa AirJet quick-start insert for US models such as 54124E and 54130E; the Lay-Z-Spa AirJet manual and ChemConnect page; MSpa’s 2023 Comfort series manual; Softub Canada’s 2026 owner’s manual; Watkins’ Aquaterra owner’s manual (document 303467); Hot Spring Highlife 2025, Jacuzzi J4 2026, Sundance 880, Bullfrog 2023, Cal Spas 2026 Platinum and Deck, Master Spas 2026 Legend, Marquis 2026 Crown, LifeSmart 110V/230V and AquaRest owner’s manuals. “See manual” means the chlorine range wasn’t part of the passage we quoted.
None of the inflatable manuals names the chemical in the tablet. In the US, the 1-inch chlorine tablets that fit these dispensers are almost always trichlor. Bestway’s Lay-Z-Spa brand in the UK sells its own ClearWater multifunction tablets (50 x 20 g) but doesn’t list the active ingredient on the product page.
Brand pages don’t always match the manuals. Lay-Z-Spa’s online chemicals guide tells owners to shock with chlorine granules and puts free chlorine at 3 to 5 ppm, while its manual says 2.0 to 4.0 ppm and warns against putting granules in the water directly. Intex’s own floating dispenser page (29044E, $9.99 and listed as out of stock on November 5, 2026) says it holds one tablet “up to 1 1/2in,” while the manuals say under 1 in. When they disagree, follow the manual that shipped with your tub, because that’s what the warranty refers to.
Why acrylic spa makers are stricter. Hot Spring’s manual says trichlor “has a very low pH (2.6) and dissolves too quickly in hot water,” and that floating dispensers “can become trapped in one area” and release chunks of sanitizer that chemically burn the shell and cover. Cal Spas says much the same about pitting and chemical blisters. An acrylic shell is a big, expensive surface, and a floater that parks against it in one spot concentrates chlorine there. Inflatable makers handle the same risk differently: a tiny one-tablet dispenser that comes out of the water before anyone gets in.
Types of chlorine tablets, and which belong in a hot tub
| Product type | Chemical | Available chlorine | Effect on water | Hot tub verdict |
|---|---|---|---|---|
| 1-inch chlorine tablets | Trichlor | Over 90% | Strongly acidic (pH about 3): lowers pH and alkalinity; adds CYA | OK one at a time in Intex, Bestway and MSpa dispensers; banned by most hard-shell makers and Softub |
| 3-inch pucks and sticks | Trichlor | Over 90% | Same, in a much bigger dose per tablet | Avoid: sized for pools and too big for spa dispensers |
| Trichlor tablets with extras (copper algaecide, clarifier) | Trichlor + additives | Varies | Copper can stain surfaces and tint water green | Avoid in a spa |
| Calcium hypochlorite tablets | Cal-hypo | Varies by product | Raises calcium hardness; Master Spas excludes cal-hypo damage from warranty | Avoid |
| Spa rapid-dissolve chlorine tabs (SpaGuard) | Dichlor + alum | Not listed | Near-neutral pH; adds CYA | OK on acrylic spas; not for soft-sided tubs or cedar |
| Chlorine cartridges (FROG @ease SmartChlor) | SmartChlor compound + minerals | Not listed | Self-regulating release, per FROG | OK where floaters are allowed |
| Spa chlorine granules (Spa 56 and similar) | Dichlor | 55.5% (dihydrate) to 62.5% (anhydrous) | Near-neutral pH (about 6 in a 1% solution); adds CYA | The chlorine most spa makers name |
Available chlorine and pH for trichlor (over 90%, pH 3.0 in a 1% solution) and dichlor (62.5% anhydrous, 55.5% dihydrate, pH 6.0) are from the specification table ChemPoint publishes for OxyChem’s ACL isocyanurates. Leisure Time Spa 56 (55%) and ProTeam Zip Chlor (62%) list matching figures on their labels, per the dealer.
The math: why one tablet at a time matters
Pool tablets are sized for pools. BioGuard’s 1-inch SilkGuard Complete tablets dose at 16 oz per 10,000 gallons, which its dealer listing says is roughly 27 tablets, so a single tablet weighs about 0.6 oz (17 g). At about 90% available chlorine, that’s roughly 15 g of chlorine. Here’s what one tablet adds if it dissolves fully:
| Tub size | Example | Free chlorine from one 1-inch tablet | Cyanuric acid added |
|---|---|---|---|
| 210 gallons | Intex 4-person square PureSpa | About 19 ppm | About 11.5 ppm |
| 290 gallons | Intex 6-person PureSpa | About 14 ppm | About 8.4 ppm |
| 400 gallons | Typical 5–6 seat plug-and-play spa | About 10 ppm | About 6.1 ppm |
| 500 gallons | Larger hard-shell spa | About 8 ppm | About 4.8 ppm |
Our math, rounded. Real readings come in lower because a tablet dissolves over days while bathers, heat and sunlight use chlorine up, which is exactly why Intex and Bestway pair a single tablet with a dispenser that limits how fast it dissolves. The risk is a pool-size floater: one that holds 3 lb of tablets carries dozens of them. Load it full in a 290-gallon tub and you’re relying on the vents alone to keep chlorine near 2 to 4 ppm.
For comparison, holding a 290-gallon tub at 3 ppm takes about 6 g (0.2 oz) of Leisure Time Spa 56 granules by the same math, a dose you can measure and adjust after every test.
On cyanuric acid: dichlor isn’t the low-stabilizer option. Every 1 ppm of chlorine from dichlor leaves about 0.9 ppm of CYA behind, against about 0.6 ppm from trichlor. If a tub uses 2 ppm of chlorine a day from dichlor, CYA climbs by roughly 55 ppm a month, past the top of Lay-Z-Spa’s 30 to 50 ppm range within a few weeks of a fresh fill. Water changes are the only practical way to bring it down. See our hot tub maintenance guide for the schedule.
The CDC goes further. Its home pool and hot tub page recommends not using cyanuric acid or chlorine products that contain it in hot tubs, and its Legionella hot tub guidance says stabilized chlorine slows disinfection. The 2024 Model Aquatic Health Code, written for public pools and spas, bars stabilized chlorine at new or renovated public spas and caps CYA at 90 ppm. That covers dichlor as well as trichlor, even though nearly every tub maker above recommends dichlor. For a home tub, the practical reading is to follow your maker’s chemical list for warranty reasons and drain often enough that CYA never builds up.
How to use chlorine tablets in an inflatable hot tub
If your manual calls for tablets (Intex, Bestway and MSpa all do), these steps follow the makers’ own instructions:
- Use the dispenser your tub came with. Intex supplies a floating chemical dispenser (part 12735 in its parts list), Bestway a chemical dispenser or ChemConnect, MSpa a 1-inch tablet dispenser. Our floater guide covers replacements.
- Start with one tablet. Intex says 1 tablet under 1 inch across. Lay-Z-Spa’s ChemConnect holds up to 4 tablets up to 2.54 cm, and Lay-Z-Spa says 2 to 3 of its 20 g tablets per 1,000 liters (about 264 gallons).
- Take the dispenser out before anyone gets in. Intex and Bestway both say to remove it while the spa is in use. Set it in a bucket, not on the vinyl.
- Never let a tablet sit on the liner. Intex says never to let chlorine touch the tub if it isn’t completely dissolved. Bestway warns that chemicals thrown directly in will settle, damage the material and discolor the PVC.
- Test before every soak. Aim for 2 to 4 ppm free chlorine and keep pH in your manual’s range (7.2 to 7.8 for Intex, 7.4 to 7.6 for Bestway US). Trichlor pulls pH and alkalinity down over time. Bestway says low pH will damage the spa and pump, and that damage from chemical imbalance isn’t covered by its warranty. Our test strip picks cover strips that read both.
- Shock separately. A tablet is maintenance, not a shock. Lay-Z-Spa says you still need to shock dose with chlorine granules. See our hot tub shock guide.
The best chlorine tablets and tablet alternatives for hot tubs
Prices are from the online store of Leisure Time Inc., an Idaho hot tub dealer, on November 5, 2026. Match the product to your tub’s manual before you buy.
1. GLB Small 1" Chlorinating Tablets — Best 1-inch tablet for Intex, Bestway and MSpa dispensers
- A plain 1-inch chlorine tablet without the copper algaecide some pool tablets add. The dealer describes it as slow-dissolving for pools and spas, for use in floaters, feeders and skimmers.
- It's the size the inflatable manuals call for: Intex wants under 1 inch, MSpa 1 inch, and Lay-Z-Spa's dispenser takes up to 2.54 cm.
- Five pounds is roughly 135 tablets by BioGuard's tablet-weight figure, which is years of one-at-a-time use in a single tub. At $18.60 a pound, it costs more per pound than spa dichlor granules.
- Not for Softub or for acrylic and rotomolded spas whose makers forbid trichlor, which is most of them (see the table above).
2. Leisure Time Spa 56 Chlorinating Granules — Best for tubs that ban tablets
- 99% sodium dichloro-s-triazinetrione dihydrate with 55% available chlorine, per the label as listed by the dealer. This is the chemical Softub, Watkins, Master Spas and LifeSmart name.
- Dissolves in seconds, so you can dose to a test strip reading instead of a tablet's release rate. At $9.80 a pound in the 5 lb tub, it was the cheapest chlorine per pound we found at the same store.
- Also useful as a chlorine shock in an inflatable, but dissolve it in a bucket of tub water first, because Intex and Bestway both warn against undissolved chlorine touching the liner.
- Same chemistry as SpaPure Chlorinating Granules ($14.99 for 1 lb) and ProTeam Di-Chlor ($22.99 for 2 lb), so buy whichever is cheapest locally.
3. SpaGuard Rapid-Dissolve Chlorinating Tabs — Best chlorine tablet for acrylic spas
- SpaGuard (BioLab's spa brand) says one tab per 300 to 600 gallons a week provides 3 to 5 ppm of free chlorine. They go in the filter compartment, not a floater, and dissolve within minutes.
- The alum clarifier coats the filter cartridge, so the dealer recommends cleaning the cartridge regularly with a chemical filter cleaner.
- The dealer's compatibility notes say they're for traditional acrylic spa surfaces and not for cedar tubs or "bleachable surfaces like soft-sided tubs." Skip them for an inflatable or a Softub.
- At $27.99 a pound, they cost the most per pound here. You're paying for a once-a-week tablet made for spas.
4. FROG @ease Floating Sanitizing System — Best hands-off chlorine
- Not a tablet but the closest thing to drop-in chlorine. FROG says SmartChlor works only with FROG minerals and self-regulates, using up to 75% less chlorine than traditional water care.
- Each SmartChlor cartridge lasts about 3 to 4 weeks, so the refills run roughly $18 to $19 a cartridge in a 3-pack.
- It floats, so check your manual. Marquis recommends FROG floating cartridges while banning other floaters, but Hot Spring doesn't recommend any floating dispenser and Softub bans them. Our hot tub sanitizer guide compares it with granules and bromine.
5. Spa bromine tablets — Best slow tablet if your tub allows a floater
- Spa chemical lines sell their slow-dissolving tablets as bromine. SpaGuard, for example, sells chlorine as granules and its 1-inch tablets as bromine (BCDMH) for a brominator or floating dispenser.
- Don't mix bromine and chlorine in the same water. Switching means a drain and refill. See our bromine vs. chlorine comparison.
Chlorine tablets we’d skip for a hot tub
- 3-inch pucks and chlorine sticks. They’re bigger than any inflatable dispenser takes (Intex says under 1 inch) and hold several times a 1-inch tablet’s chlorine.
- Tablets with additives. BioGuard SilkGuard Complete 1” Tabs ($52.99 for 4.5 lb) are sold for small pools and include copper-based algae-killing crystals. Copper is one cause of green water and staining in a spa (see our green water guide).
- Calcium hypochlorite tablets. The dealer’s FreshWater listing notes that cal-hypo raises calcium hardness with every dose, which ends in scale on heaters.
- Mixing chemicals in one dispenser. The dealer’s BioGuard listing warns that mixing trichlor with another pool chemical, calcium hypochlorite shock in particular, inside a skimmer, feeder or floater can cause a fire or explosion. Intex also says never to mix chemicals together.
If your chlorine is too high after using tablets
- Take out the dispenser and any tablet remains, and keep everyone out of the water.
- Test free chlorine and pH. A high chlorine reading with a low pH is the typical trichlor result.
- Open the cover and run the bubbles or jets so chlorine can gas off. Hot, aerated water loses chlorine quickly once the source is gone.
- Wait until you’re under your maker’s maximum (Intex lists 5 ppm) before anyone soaks.
- Fix pH and alkalinity. If pH has dropped below 7.2, raise total alkalinity first, then pH. Our pH guide covers the opposite problem and the same test routine.
- Drain if it won’t come down. A partial drain and refill is the quickest fix. Our guide on how to drain a hot tub walks through it.
The bottom line
Chlorine tablets are right for some hot tubs and wrong for others, and the tub’s own manual decides. Intex, Bestway and MSpa inflatables are designed for one small (1-inch) chlorine tablet in their included dispenser, taken out while you soak. Softub and most acrylic and rotomolded spa makers, including Hot Spring, Jacuzzi, Bullfrog, Cal Spas, Master Spas and Marquis, forbid trichlor tablets or exclude the damage from warranty, and name sodium dichlor granules such as Leisure Time Spa 56 instead. Acrylic spa owners who want a weekly tablet can use SpaGuard Rapid-Dissolve Chlorinating Tabs. Whatever you use, one tablet holds far more chlorine than a few hundred gallons need at once, so test before every soak. Our hot tub chemicals guide covers the rest of the kit.
Sources (all read November 5, 2026): Intex PureSpa owner’s manuals 381PO and 380PO (2025), intexcorp.com spa water maintenance and floating dispenser 29044E pages; Bestway SaluSpa AirJet US quick-start insert; Lay-Z-Spa AirJet manual, ChemConnect page, chemicals guide and ClearWater tablet page; MSpa 2023 Comfort manual; Softub Canada 2026 owner’s manual; Watkins Aquaterra owner’s manual 303467; Hot Spring Highlife 2025, Jacuzzi J4 2026, Sundance 880, Bullfrog 2023, Cal Spas 2026, Master Spas 2026 Legend, Marquis 2026 Crown, LifeSmart and AquaRest owner’s manuals and warranties; SpaGuard product pages; ChemPoint/OxyChem ACL isocyanurate specifications; Trouble Free Pool glossary (trichlor, dichlor); CDC home pool and hot tub water treatment page and Legionella hot tub module; CDC Model Aquatic Health Code, 5th edition (2024); product listings at shop.leisuretimeinc.com.