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Hot tub chlorinator

Updated: 16.10.2026

You have a Lay-Z-Spa or another small tub, and the pool chlorinators in the search hold far more water than you do. A hot tub chlorinator has to match about 1,400 litres, and a different rule if you let the tub. Pool cells at 6 g/h or 12 g/h stay in the frame-pool row. The full table is the [pool chlorinator](/hub/pool-care/pool-chlorinator) comparison. The Products Compared editorial team wrote this from the amazon.co.uk captures, HSE HSG282 and a Scottish holiday-let note on 16 October 2026. Nobody ran a lab test. A qualifying purchase through our links can earn a commission at no extra cost to you.

You have a Lay-Z-Spa or another small tub, and the pool chlorinators in the search hold far more water than you do. A hot tub chlorinator has to match about 1,400 litres, and a different rule if you let the tub.

Our top picks

FENRIR FENRIR 5 inch floater

Best overall

FENRIR FENRIR 5 inch floater
9.0/10about £5.99
View offer
Briidea Briidea BR-159

Alternative

Briidea Briidea BR-159
8.8/10about £169.89
View offer
Bestway Bestway Hydrogenic 0.5 g/h

Rank 3

Bestway Bestway Hydrogenic 0.5 g/h
8.2/10about £185.57
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On this page
  1. 1.A hot tub is not a small swimming pool
  2. 2.The Bestway 0.5 g/h listing
  3. 3.A tablet floater or a drop-in cell
  4. 4.Your tub at home, or a tub you let

A hot tub is not a small swimming pool

A family inflatable tub is a few hundred to about 1,400 litres of warm water. Bestway’s 6 g/h cell states pools up to 26,498 litres. Intex 26670 states 12 g/h and at least 2,650 litres per hour. Both are the wrong volume for a Lay-Z-Spa. Bestway’s 0.5 g/h unit draws the line at 1,400 litres. A spliced third-party cell, or seawater in the tub, is outside what this comparison supports. The full-size type decision is the pool chlorinator buying guide. If you already own the device, the order of test and dose is how to use a pool chlorinator.

The Bestway 0.5 g/h listing

The spa unit in this capture is Bestway Lay-Z-Spa Hydrogenic, ASIN B0D9YWTDRD, at £185.57, rated 4.1 from 42 reviews. It states 0.5 g/h and a cap of 1,400 litres. The bullets describe a rechargeable battery of about eight hours, while the power field says ac. Confirm which line is in the box before you assume a 13 A socket. The file has no United Kingdom review text for this ASIN, so 4.1 from 42 is a star line only. It makes chlorine from salt, so you still test. ASIN B0D7J41B67 is a different listing, labelled a US import, at about £11.90. That price is not a discount on B0D9YWTDRD. For a family tub inside 1,400 litres, this is the device that states the cap. Skip it above that volume, past about eight hours without a recharge, or while the power lines still clash.
FENRIR FENRIR 5 inch floater

Testsieger

FENRIR FENRIR 5 inch floater
9.0/10about £5.99
View offer

A tablet floater or a drop-in cell

FENRIR, ASIN B08C56HWDZ, is £5.99 and 4.5 from 2,439 reviews, and UK reviews do put floaters in hot tubs. Those reviews also describe lids that open and tablets that fall out. In about 1,400 litres a puck on the floor is a large dose. Use one only if you test before each soak and check the lid. Briidea BR-159, ASIN B0F61ZDP4S, is the drop-in at £169.89, rated 4.4 from 66 reviews. The title says up to 2,000 gallons, with no voltage and no UK review in the file. There is no 1,400 litre cap to set beside Bestway, so leave the gallons as the title’s unit.

Your tub at home, or a tub you let

HSG282 is the Health and Safety Executive book on spa-pool risks. Paragraph 75 puts a private tub for the owner, family and occasional guests, with no financial gain, outside that guidance. Paragraph 76 puts a let or a hotel tub inside it, and the text expects disinfection by an inline feeder. A private tub can use the 0.5 g/h unit inside 1,400 litres, or a floater if you test and keep the lid locked. A holiday let is a different duty. Argyll and Bute’s note says a single let still wants a residual disinfectant, and that inflatable spas are not for commercial use. If you take money for the tub, use an inline feeder and competent water treatment, and read HSG282 before guests arrive.

Common questions

What does the 0.5 g/h unit actually state?
ASIN B0D9YWTDRD states 0.5 g/h and up to 1,400 litres, at £185.57 and 4.1 from 42 reviews. The bullets describe a battery of about eight hours. It produces chlorine from salt, so a no-chlorine slogan contradicts the output. The capture has no UK review text. You still test free chlorine and pH. The grams per hour are a production rate, not a promise the residual is correct when you get in.
Is it mains or battery?
The bullets say a battery of about eight hours. The power field on the same capture says ac. Treat that clash as unresolved until the live page and the manual agree. Plan on a recharge at around eight hours if the battery line is the one in the box. Do not assume a BS 1363 plug the listing has not shown. A pool cell with a euro-plug complaint is a different ASIN.
Can I use a £6 floater in a hot tub?
On a private tub, yes, if you test and keep the lid locked. FENRIR is £5.99, and UK reviews include hot-tub use alongside lids that open. A fallen tablet in 1,400 litres is a heavy dose, and trichlor on vinyl can mark the shell. CMXOAJ at £6.99 has a crack report in a hot tub and a note about crushing 3 inch tablets. Whole small tablets and a test before you soak are the conditions. A floater is not the HSG282 answer for a let.
Does a private tub have to follow HSG282?
Paragraph 75 says a tub used by the owner, family and occasional guests, with no financial gain, sits outside HSG282. You still owe the people in the water a sensible residual, which means a test kit and a device that fits the litres. The 0.5 g/h unit or a watched floater is a domestic choice inside that paragraph. It becomes the wrong reliance as soon as money changes hands.
What changes if I let the tub?
Paragraph 76 brings a let or hotel tub into HSG282, and the book expects an inline feeder. Argyll and Bute adds that a single let should hold a residual disinfectant, and that inflatable spas are not for commercial use. The £185.57 rechargeable unit and the £5.99 holder were not assessed here as commercial treatment. If the tub is a holiday let, read HSG282 and get competent water-treatment advice before guests arrive.

Related pages

Salt chlorinator or chlorine floater

Hot tub algae and biofilm

Pool chlorinator

Best pool chlorinator 2026: top pick or best value

Pool chlorinator buying guide: litres, flow and plug

How to use a pool chlorinator: floater or salt cell

Sources

Public UK sources from the research digest, retrieved 16 October 2026. Prices, stars, and review counts are the amazon.co.uk captures for these ASINs.

  1. HSE, swimming pool safety management (retrieved 16.10.2026)
  2. HSE, HSG179, health and safety in swimming pools (retrieved 16.10.2026)
  3. HSE, using biocides safely (retrieved 16.10.2026)
  4. HSE, biocide product types (retrieved 16.10.2026)
  5. PWTAG TN60, free chlorine and pH (retrieved 16.10.2026)
  6. SPATA, salt chlorinators factsheet (retrieved 16.10.2026)
  7. BSI, BS EN 16401:2013, sodium chloride for electrochlorinators (retrieved 16.10.2026)
  8. Sunshine Pools, Bestway Hydrogenic 6 g/h (retrieved 16.10.2026)