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Chlorine tablet size for a floater

Updated: 23 October 2026

You are holding a tub of tablets and a floater listing, and the words do not match. One packet says 20 g. Another says 1.5 inch. A third is a 3 inch puck. The listing may say 5 inch, which is often the float, not the tablet. Chlorine tablet size for a floater is the fork that decides the purchase. Match the tablet in your hand to the size the listing names. The eleven rows are on the [dosing float comparison](/hub/diy-supplies/dosing-float). Peter F. checked the stored listings, not a lab. A qualifying purchase can earn a commission at no extra cost to you.

You are holding a tub of tablets and a floater listing, and the words do not match. One packet says 20 g. Another says 1.5 inch. A third is a 3 inch puck.

Our top picks

Gre Gre FDP20 20 g float

Best overall

Gre Gre FDP20 20 g float
8.6/10about £11.82
View offer
Jonuin Jonuin turtle floater

Alternative

Jonuin Jonuin turtle floater
8.2/10about £12.99
View offer
NEIQIUWING NEIQIUWING 1.5 inch float

Alternative

NEIQIUWING NEIQIUWING 1.5 inch float
0.0/10about £6.36
View offer
On this page
  1. 1.The two sizes UK shops actually sell
  2. 2.What this set claims
  3. 3.When a big float still rejects a small tablet
  4. 4.Dose lines that do not travel

The two sizes UK shops actually sell

UK pool shops usually sell two slow tablets for a dispenser. 123 Pools states 20 g, about 1 inch, for hot tubs and small pools, and 200 g, about 3 inch, for larger pools. Happy Hot Tubs uses the same split. Both sizes go in a dispenser, not on the liner. The word about is the shop describing its own tablets. The large tablet is the 200 g puck, about 3 inch, about 7.6 cm on the Intex page at 123 Pools. Steinbach’s maker page for the Mini says tablets up to 20 g. The amazon title says 20 g. Neither line invites a 200 g puck.

What this set claims

Two listings state 20 g and stop there. The Steinbach Mini at £5.39 and the Gre FDP20 at £11.82 do not state 3 inch or 200 g. If the tablet in your hand is a puck, they are the wrong rows. A named 20 g pick, on that condition only, is on best chlorine float UK. NEIQIUWING, at £6.36, is the only listing that says 1.5 inch, with no review of the fit. Do not round it to 20 g or to a 200 g puck. Jonuin claims five 3 inch or forty 1 inch tablets. ZWOOS and Gaethra claim several 3 inch tablets. That is a capacity claim, not proof that 3 inch equals 200 g on that ASIN. EduPlayte and Feirdhoo use 5 inch for the body. Feirdhoo’s table says 8 × 8 × 1 cm. Acunny does not state a tablet size.
Gre Gre FDP20 20 g float

Testsieger

Gre Gre FDP20 20 g float
8.6/10about £11.82
View offer

When a big float still rejects a small tablet

A large chamber is not a universal hopper. Happy Hot Tubs’ large dispenser, about 175 mm high and 200 mm across, takes 200 g or 20 g. Discount Pool Store’s large floater is for 200 g and says it is not for 20 g tablets. Inside this set, Gaethra’s bullets claim four 3 inch tablets and the table says 8 × 7 × 6 cm. Four pucks of about 7.6 cm cannot occupy that body. ZWOOS lists 19 × 18 × 12 cm beside its four-tablet claim, which is a plausible envelope, though no United Kingdom review in the file counts the pucks that seated. Buy the body that names your tablet.

Dose lines that do not travel

The number of tablets on a label belongs to that tablet. Pool Warehouse’s 200 g label is one UK example: about two tablets per 32 m³ in a floating dispenser, with 2–3 mg/l and pH 7.2–7.6. Putting two tablets into a 20 g mini, or treating 32 m³ as a paddling pool, is how you overdose. Do not copy it onto the Steinbach or the Gre. Deep Blue’s 20 g notes talk about 1–3 mg/l in a pool and 3–5 mg/l in a hot tub, with pH 7.2–7.6. Those figures belong to that tablet. Happy Hot Tubs’ start with three or four, not seven, belongs to their small dispenser. When the size in your hand matches the listing, how to use a chlorine float can take over. Until it matches, do not snap a puck to fit a mini.

Common questions

Are 20 g and 1 inch the same tablet?
UK shops often say 20 g is about 1 inch, and 200 g is about 3 inch. That is their wording, from pages such as 123 Pools and Happy Hot Tubs, not a line printed on every float in this set. Steinbach and Gre say 20 g. They do not say 1 inch. Jonuin says 1 inch and 3 inch.
Will my 200 g puck fit the Steinbach mini?
No. The amazon listing says 20 g. The maker page says tablets up to 20 g. A 200 g puck is the large tablet, and it does not belong in that chamber. Forcing it will leave the lid open or the tablet against a surface. Gre’s FDP20 is the same 20 g limit.
What is a 1.5 inch tablet, and which float says that?
NEIQIUWING is the only listing in this set that says 1.5 inch. It is £6.36, about 12 cm tall, with a claimed thermometer and no reviews. A 1.5 inch tablet is not the 20 g size 123 Pools describes, and it is not a 3 inch puck. If your tablets say 1.5 inch, this is the row that uses the same figure.
Does 5 inch mean the tablet or the float?
On EduPlayte and Feirdhoo it is a body claim. EduPlayte does not state a tablet size. Feirdhoo’s table says 8 × 8 × 1 cm, which fights the 5 inch title. Bestway’s 5 inch floater, outside this set, is specified for 1 inch tablets. A 5 inch title is not a 5 inch puck, and it is not permission to use a 3 inch tablet. Read the tablet line.
How many 3 inch tablets does a solar float really hold?
The listings claim up to four. ZWOOS says up to four 3 inch, or many 1–2.5 inch, and its dimensions are 19 × 18 × 12 cm. Gaethra says four 3 inch and then prints 8 × 7 × 6 cm, which cannot be the same object. No United Kingdom review in these files counts the tablets that actually fitted. Treat four as a seller’s ceiling, and treat a contradictory centimetre line as a reason to walk away.

Related pages

Dosing float buying guide

Dosing float

Best chlorine float UK: top pick and best value 2026

Chlorine float for a hot tub, not a let-spa feeder

How to use a chlorine float: lid, ring, place, test

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 22.10.2026.

  1. HSE: HSG179, Managing health and safety in swimming pools (retrieved 22.10.2026)
  2. HSE: Swimming pools (retrieved 22.10.2026)
  3. HSE: HSG282, Control of legionella and other infectious agents in spa-pool systems (retrieved 22.10.2026)
  4. PWTAG: Code of Practice (retrieved 22.10.2026)
  5. PWTAG: Technical note 68, swimming pool chemicals (retrieved 22.10.2026)
  6. Pool Warehouse UK: chlorine tablets 5 kg (retrieved 22.10.2026)
  7. Consumer Rights Act 2015 (retrieved 22.10.2026)