Outdoor pool with a pump
You want a slow 200 g tablet and you will test free chlorine and pH. Relax names trichloroisocyanuric acid, the pack figures agree on 5 kg, and the review file is the longest here. No floater is in the box.
Chlorine tablets pool comparison 2026
The best chlorine tablets for pools, compared.
Top pick: Deep Blue stabilised 200 g tablets Best value: Deep Blue 5 kg 20 g multifunction tablets – Lowest price among agreed 5 kg listings at 4.3 or above with at least 100 reviews, at about £21.98. Updated 16.10.2026.
Chlorine tablets for pools are slow-dissolving solid sanitisers sold on amazon.co.uk as 200 g pucks, 20 g tablets, or small kits with a floater. You use them to hold a free-chlorine residual in an outdoor pool or, with the small tablets, in a hot tub. Quality here means a named chemistry, a pack weight the listing agrees with, and a tablet that fits the floater, skimmer, or feeder you already have. It is a poor match for a pool feeder built for a 200 g puck. How the two chemistries differ is set out in the [multifunction versus stabilised tablets](/hub/pool-care/chlorine-tablets-pool/sub/chlorine-tablets-pool-multifunction-vs-stabilised) guide. Nothing here is a lab test, a kill rate, or a market-size claim.
Chlorine tablets for pools are slow-dissolving solid sanitisers sold on amazon.co.uk as 200 g pucks, 20 g tablets, or small kits with a floater.
24 products checked · 58 hrs invested · +21,400 readers
7 of 7: Best chlorine tablets for pools compared
Swipe for more
1-2 of 7Best overall
Best value
7.3/10
8.8/10
8.1/10
8.4/10
5.2/10
4.6/10
6.1/10
∼ £31
∼ £27
∼ £28
∼ £22
∼ £13
∼ £17
∼ £25
4.7(80)
4.6(264)
4.6(147)
4.6(130)
4.0(12)
3.8(25)
–
Personal buying guide
Which chlorine tablets fit?
Question 1 of 2
Where will you use the tablets?
The best chlorine tablets for pools in detail
Our view
The Deep Blue DBPCLTAB2002-1X1kg listing is a 200 g stabilised tablet at about £31.49, the highest price in this set, and the bullets call it a pure stabilised sanitiser rather than a multifunction tablet. Cyanuric acid is named, and the listing tells you to dose algaecide and clarifier separately. The printed dose is one tablet per 25,000 litres a week, with free chlorine at 1–3 ppm and pH at 7.2–7.6, which belongs to this label only. It shows 4.7 from 80 reviews, the highest star line here. Reviews also say the tablets are palm-sized and hard to fit in a small dispenser. The title and the package size say 5 kg, while the unit count is 1,000 g, the item weight is 1 kg and the model says 1 kg. That conflict is unresolved, so the star line does not make this the top pick. It fits a buyer who wants stabilised chlorine without the extras and can live with not knowing whether the box is 1 kg or 5 kg.
Pros
- Highest star line in the set, 4.7 from 80 reviews
- Cyanuric acid is named, and the listing says it is not multifunction
- A weekly litre dose is printed, plus 1–3 ppm and pH 7.2–7.6
- A skimmer, floater or automatic dosing is stated
Cons
- The title says 5 kg; the unit count, weight and model say 1 kg
- About £31.49, and a price per kilo cannot be settled
- Palm-sized tablets that reviews say are hard to fit in a small dispenser
- Algaecide and clarifier are still separate purchases
Best for: A large outdoor pool if you want to dose algaecide yourself and you will confirm the kilograms on the parcel.
Less suitable: A small dispenser, a buyer who needs a settled 5 kg price per kilo, or anyone who wanted clarifier in the tablet.
Specifications
- Model
- Deep Blue stabilised 200 g tablets
- Brand
- Deep Blue
- Price
- ∼£31
- Customer rating
- 4.7/5(80)
- Tablet type
- Stabilised chlorine
- Tablet size
- 200 g
- Pack weight
- Title 5 kg; weight 1 kg
- Where it goes
- Skimmer, floater or dosing
- Stabiliser
- Yes
- Algaecide
- No
- Clarifier
- No
- Chemical
- Cyanuric acid
- Dose stated
- Yes
Common questions
Is this the multifunction Deep Blue tub?
No. The bullets call it a pure stabilised sanitiser and say to dose algaecide and clarifier separately. Cyanuric acid is named. The other Deep Blue 200 g listing in this set is the multifunction one.
Is the tub 5 kg or 1 kg?
The title and the package-size name say 5 kg. The unit count is 1,000 g, the item weight is 1 kg, and the model is DBPCLTAB2002-1X1kg. The raw file does not settle it.
What dose does the listing print?
One tablet per 25,000 litres a week, and a line to hold free chlorine at 1–3 ppm and pH at 7.2–7.6. That is the listing’s own text. Reviews also say the tablets are palm-sized and hard to fit in a small dispenser.
Our view
The Relax tub is 25 tablets of 200 g, also called 3 inch, in a 5 kg pack the title, the unit count and the item weight all agree on, at about £26.99. The highlight names trichloroisocyanuric acid, and the bullets add stabiliser, algaecide and clarifier, which no other listing in this set does together. It shows 4.6 from 264 amazon.co.uk reviews, the largest review file here. The listing does not say where a tablet goes, and no floater is included. Reviews mention a dispenser and a skimmer basket, and one reviewer with a 7,750 litre pool says a tablet lasts about two weeks in a dispenser, which is one report rather than a dose. One buyer found split blocks and chlorine dust that irritated their throat, and another says the tablets crumble and do not hold chlorine as well as other products. A later order was late and substituted, and one buyer thought they had ordered pure chlorine. It is the top pick when you want that named chemistry and that review count, and you will still open the tub and look for dust.
Pros
- 25 tablets of 200 g in a 5 kg pack the title, unit count and weight agree on
- Trichloroisocyanuric acid, stabiliser, algaecide and clarifier are named
- 4.6 from 264 reviews, the largest file in this set
- One 7,750 litre review reports about two weeks in a dispenser
Cons
- No floater, and the listing does not say where a tablet goes
- Split blocks and chlorine dust in one review, with throat irritation
- Crumble complaints, a late substituted order, and a buyer who expected pure chlorine
Best for: An outdoor pool with a dispenser or skimmer you already own, if you want the most reviewed 200 g multifunction tub in this set.
Less suitable: A hot tub, a small dispenser that cannot take a 3 inch puck, or anyone who wanted chlorine with nothing else in the tablet.
Specifications
- Model
- Relax 5 kg multifunction tablets
- Brand
- Relax
- Price
- ∼£27
- Customer rating
- 4.6/5(264)
- Tablet type
- Multifunction
- Tablet size
- 200 g (3 inch)
- Pack weight
- 5 kg, 25 tablets
- Where it goes
- Not stated
- Stabiliser
- Yes
- Algaecide
- Yes
- Clarifier
- Yes
- Chemical
- Trichloroisocyanuric acid
- Dose stated
- No
Common questions
What is in the Relax 5 kg tub?
25 tablets of 200 g, also described as 3 inch. The bullets say chlorine, stabiliser, algaecide and clarifier. The highlight names trichloroisocyanuric acid. No floater is included.
Where does the listing say to put a tablet?
It does not. Reviews mention a dispenser and a skimmer basket. One reviewer with a 7,750 litre pool says a tablet lasts about two weeks in a dispenser. That is one review, not a dose instruction.
What problems show up in the reviews?
One buyer found split blocks and chlorine dust that irritated their throat. Another says the tablets crumble and do not hold chlorine as well as other products. A second order was late and substituted. One buyer thought they were ordering pure chlorine.
Our view
The Deep Blue DBPMFTAB2005-1X5kg listing is 200 g multifunction tablets at about £28.23, and the bullets place them in a skimmer, a dosing chamber or a floater. They state stabilised chlorine, a clarifier and an algaecide, for a pool or a hot tub, and one bullet also says indoor and outdoor pools. The chlorine compound is not named, and no dose is printed. The title, the 5,000 g unit count, the 5 kg item weight and the model number say 5 kg, while the item-type name says 1 kg. It shows 4.6 from 147 reviews. One reviewer says the tablets dissolve a bit too quickly, and another says one large tablet was gone in about 36 hours in a skimmer with the pump running constantly. That same review warns against leaving tablets in the skimmer when the pump is off, and the tablet count is not stated. Choose it when you need the feeder named on the page, and weigh the parcel because of the 1 kg line.
Pros
- A skimmer, dosing chamber or floater is stated
- Stabiliser, clarifier and algaecide are stated
- Title, unit count, item weight and model say 5 kg
- 4.6 from 147 reviews
Cons
- The item-type name says 1 kg
- The chlorine compound and the dose are not stated
- Reviews of a fast dissolve, including about 36 hours with the pump on
- The tablet count is not stated
Best for: A pool that already has a skimmer, dosing chamber or floater, if you will weigh the tub on arrival.
Less suitable: A hot tub that cannot take a 200 g puck, or a skimmer you leave full while the pump is off.
Specifications
- Model
- Deep Blue 5 kg 200 g multifunction tablets
- Brand
- Deep Blue
- Price
- ∼£28
- Customer rating
- 4.6/5(147)
- Tablet type
- Multifunction
- Tablet size
- 200 g
- Pack weight
- 5 kg; name says 1 kg
- Where it goes
- Skimmer, chamber or floater
- Stabiliser
- Yes
- Algaecide
- Yes
- Clarifier
- Yes
- Dose stated
- No
Common questions
Where can these 200 g tablets go?
The bullets say a skimmer, a dosing chamber or a floater. They describe stabilised chlorine, a clarifier and an algaecide, for a pool or a hot tub. One bullet also says indoor and outdoor pools.
Is the pack 5 kg or 1 kg?
The title, the 5,000 g unit count, the 5 kg item weight and the model number DBPMFTAB2005-1X5kg say 5 kg. The item-type name says 1 kg. Both are on the listing.
What do reviews say about dissolve time?
One reviewer says they dissolve a bit too quickly. Another says one large tablet was gone in about 36 hours in a skimmer with the pump running constantly, and warns against leaving tablets in the skimmer when the pump is off.
Our view
The Deep Blue DBMFTAB2025-1X5kg tub is 5 kg of 20 g multifunction tablets at about £21.98, and the title and the item weight both say 5 kg. The bullets call them small tablets with stabilised chlorine, a clarifier and an algaecide, for hot tubs, spas and swimming pools. The chlorine compound is not named, the listing does not say where the tablet goes, and it prints no dose. On amazon.co.uk it shows 4.6 from 130 reviews. Most of the 22 reviews in the raw file are short praise from hot-tub users, and one reviewer says the tablets last only two or three days and that they need twice as many. The unit-count field says 1.0 count against that 5 kg weight. This is the best value when you want the small tablet and a review file of this size, and it is a poor match if you need a slow 200 g puck for a pool feeder.
Pros
- 20 g tablets, the small size in this set
- About £21.98, with the title and the item weight both saying 5 kg
- Stabiliser, clarifier and algaecide are stated
- 4.6 from 130 reviews, mostly from hot-tub users
Cons
- No feeder and no dose on the listing
- The chlorine compound is not named
- One review says two or three days, then twice as many tablets
- The unit count says 1.0 count
Best for: A hot tub or spa where the reviews in this file already use the 20 g size.
Less suitable: An outdoor pool feeder built for a 200 g puck, or anyone who needs a printed dose.
Specifications
- Model
- Deep Blue 5 kg 20 g multifunction tablets
- Brand
- Deep Blue
- Price
- ∼£22
- Customer rating
- 4.6/5(130)
- Tablet type
- Multifunction
- Tablet size
- 20 g
- Pack weight
- 5 kg; count says 1
- Where it goes
- Not stated
- Stabiliser
- Yes
- Algaecide
- Yes
- Clarifier
- Yes
- Dose stated
- No
Common questions
What size are the Deep Blue tablets in this 5 kg tub?
20 g. The bullets call them small multifunction tablets with stabilised chlorine, a clarifier and an algaecide. The title covers hot tubs, spas and swimming pools.
Does the listing say where to put them?
No. It does not name a skimmer, floater or feeder. It also does not give a dose.
What do the reviews say?
Most of the 22 reviews in the raw file are short praise from hot-tub users. One reviewer says the tablets last only two or three days and that they need twice as many.
Our view
The SINPY CT04 kit is a bottle of small tablets plus a 5 inch floater, listed at about £12.99, with a title dose of seven tablets per 2,500 gallons a week. The listing never says which gallon that is, and it never names the chlorine compound. The title says 100 g of tablets, the unit count says 220 g, and the item weight is 180 g, so the fill is not settled. On amazon.co.uk it shows 4.0 from 12 reviews. One UK review likes the floater and says the small tablets are not great, and another says the tablets did nothing for a spa and the buyer is going back to granules. A third review in the file is about a pool heater, not these tablets. Treat the box as a floater and a short fill, and weigh it when it arrives.
Pros
- 5 inch floater with adjustable dose control is in the box
- About £12.99, the lowest price in this set
- Resealable bottle, as a listing line
- 4.0 from 12 amazon.co.uk reviews
Cons
- Title 100 g, unit count 220 g and item weight 180 g do not agree
- Chlorine compound is not stated
- One spa review says the tablets did nothing, and one review is about a heater
Best for: A first weekend with an inflatable pool if the floater is what you want and you will weigh the fill when the parcel arrives.
Less suitable: Anyone who needs a named chemical, an agreed pack weight, or enough tablets for a season.
Specifications
- Model
- SINPY tablet and floater set
- Brand
- SINPY
- Price
- ∼£13
- Customer rating
- 4.0/5(12)
- Tablet type
- Not stated
- Tablet size
- Small tablets
- Pack weight
- 100 g, 220 g, 180 g
- Where it goes
- 5 inch floater
- Dose stated
- Yes
Common questions
How much chlorine does the SINPY listing say is in the box?
The title says 100 g of tablets plus a 5 inch floater. The unit count is 220 g and the item weight is 180 g. Those three figures do not match, so the fill is not settled.
Does the listing include a floater?
Yes. It is a 5 inch floating dispenser with adjustable dose control, as a listing line. The tablets go inside that floater.
What do the reviews say about the tablets?
One UK review likes the floater and says the small tablets are not great. Another says the tablets did nothing for a spa and the buyer is going back to granules. One review in the file is about a pool heater, not these tablets.
Our view
The Bulla orange-cl kit is 1 inch tablets, a screw-cap floater and 50 pH test strips, listed at about £16.99. The dose on the listing is seven tablets per 2,500 gallons, and the gallon type is not stated. The title says multifunction, but the bullets do not list stabiliser, algaecide or clarifier. The title says 1 lb, the unit count says 500 g and the item weight is 670 g. It shows 3.8 from 25 amazon.co.uk reviews. Several reviewers say the tablets do not dissolve, including after two days in the dispenser, or that a whole bucket barely moved the chlorine reading, and two reviews say the instructions are unclear or in broken English. Other reviews still call it a useful starter kit. A bullet that says the tablets can go straight into the pool is a listing line for this kit, not a method to copy onto a larger puck.
Pros
- 1 inch tablets, a screw-cap floater and 50 pH strips in one box
- About £16.99
- Some reviewers treat it as a starter kit
- Ranked 27 in Chlorine on amazon.co.uk
Cons
- Repeated reviews that the tablets do not dissolve
- Instructions described as unclear or in broken English
- Multifunction is in the title only; the bullets do not list the ingredients
- 1 lb, 500 g and 670 g do not agree
Best for: Someone who wants strips and a floater together and will watch whether the 1 inch tablets actually shrink.
Less suitable: A pool you need to hold at a chlorine reading, or anyone who cannot read the label.
Specifications
- Model
- Bulla 1 lb tablet kit with floater
- Brand
- Bulla
- Price
- ∼£17
- Customer rating
- 3.8/5(25)
- Tablet type
- Title only
- Tablet size
- 1 inch
- Pack weight
- 1 lb, 500 g, 670 g
- Where it goes
- Floater included
- Dose stated
- Yes
Common questions
What is in the Bulla kit?
The bullets say one pool dispenser, 1 lb of chlorine tablets and 50 pH test strips. The title says the tablets are 1 inch. The unit count is 500 g and the item weight is 670 g, so the pack figures do not agree.
Does the listing list stabiliser, algaecide and clarifier?
No. The title says multifunction. The bullets do not name those ingredients. The benefits field says it kills algae and prevents algae growth.
What do UK reviews say about dissolving?
Several say the tablets do not dissolve, including after two days in the dispenser, or that a whole bucket barely moved the chlorine reading. Two reviews say the instructions are unclear or in broken English. Other reviews call it a useful starter kit.
Our view
The ChlorineXpress CT-5KG-200 container is about 25 slow 200 g tablets, and the title, the 5,000 g unit count and the item weight all say 5 kg, at about £24.99. The bullets describe stabilised chlorine with cyanuric acid for outdoor pools, used in a floating dispenser, a skimmer or an automatic feeder. They do not list a clarifier, they do not call the tablet multifunction, and the chlorine compound is not named. Algae prevention on the listing is tied to keeping chlorine and pH correct, not to an algaecide in the puck. There is no numeric dose, only a line about steady dosing rather than daily dosing. There is no customer-review line and no review text in the raw file, so praise and complaints are unknown, and the Chlorine rank of 349 is a sales rank rather than a water test. It is the agreed 200 g stabilised pack in this set only if you can accept a tub nobody here has reviewed.
Pros
- About 25 tablets of 200 g, and the title, unit count and weight all say 5 kg
- Cyanuric acid is named as the stabiliser
- A floater, skimmer or automatic feeder is stated
- About £24.99
Cons
- No star line and no review text in the raw file
- The chlorine compound is not named
- No clarifier and no numeric dose
Best for: An outdoor pool with a feeder, if you will judge the first tub yourself because this file has no reviews.
Less suitable: Anyone choosing from stars, or anyone who wants algaecide and clarifier in the puck.
Specifications
- Model
- ChlorineXpress 5 kg 200 g stabilised tablets
- Brand
- ChlorineXpress
- Price
- ∼£25
- Tablet type
- Stabilised chlorine
- Tablet size
- 200 g
- Pack weight
- 5 kg, about 25
- Where it goes
- Floater, skimmer or feeder
- Stabiliser
- Yes
- Algaecide
- No
- Chemical
- Cyanuric acid
- Dose stated
- No
Common questions
Are these multifunction tablets?
No. The bullets describe slow-dissolving stabilised chlorine with cyanuric acid for outdoor pools. They do not list a clarifier. Algae prevention is tied to keeping chlorine and pH correct, not to an algaecide ingredient.
How many tablets are in the tub?
About 25 tablets of 200 g, in a 5 kg container. The title, unit count and item weight all say 5 kg.
Is there a star rating in the raw file?
No. There is no customer-review line and no review text, so praise and complaints are unknown here.
How we compared
Seven amazon.co.uk listings were scored from the capture in this category. Prices, stars, and review counts are those UK lines, not a live re-check and not a lab test. The score moves with the star line and the review count, whether the chemistry is named, whether the title and the weight agree, and review complaints such as dust, tablets that do not dissolve, or a puck gone in about 36 hours. A missing star line keeps the score low. The four weights below sum to 100.
1
Stars and review count
35%The amazon.co.uk star line counts, and a larger written review file counts for more than a tenth of a star. No star line in the raw file keeps the score low even when the pack figures agree.
2
Named chemistry
25%Points depend on whether the listing names the chlorine compound, and whether a multifunction title actually lists stabiliser, algaecide, and clarifier.
3
Pack weight agrees
20%The title, the unit count, and the item weight should agree. An unresolved 1 kg versus 5 kg pack is a deduction. A price per kilo is used only when they agree on 5 kg.
4
Review complaints
20%Chlorine dust, tablets that do not dissolve, a puck gone in about 36 hours, and instructions the buyer could not read are deductions taken from the review file.
Independent review
Last updated: 16.10.2026
8 sources checked
Chlorine tablets for pools buying guide
Match the tablet to the water you are treating, the feeder you already own, and a pack whose title and weight tell the same story. A 200 g puck and a 20 g hot-tub tablet are not substitutes. The seven rows are amazon.co.uk listings from this capture. They are not a lab ranking, and they are not a dose you can copy from one tub onto another.
What are chlorine tablets for pools?
Chlorine tablets for pools are slow-dissolving solid sanitisers for swimming-pool water. On amazon.co.uk they are sold as 200 g pucks, 20 g tablets, or small kits that include a floater. You use a 200 g puck to hold a free-chlorine residual in an outdoor pool that already has a pump. The 20 g tablets in this set are the size reviewers use in a hot tub. Stars on this page are amazon.co.uk scores. Nothing here is a lab test, a kill rate, or a market-size claim.
Best for
- Outdoor-pool owners with a pump who will test free chlorine and pH
- Hot-tub owners matching the Deep Blue 20 g reviews
- First-time owners of a small or inflatable pool who will weigh the kit
Not ideal for
- A hot tub or paddling pool if the only tablet on offer is a 200 g puck
- Anyone who needs the Deep Blue stabilised listing settled as 1 kg or as 5 kg
- A public or work pool, which sits under the PWTAG Code of Practice
Mistakes to avoid
- 1
Buying a 200 g puck for a hot tub
The hot-tub size in this file is the Deep Blue 20 g tablet. A 200 g puck is palm-sized. Reviews of the stabilised Deep Blue listing say that size is hard to fit in a small dispenser. A heavier bucket does not make it the right object.
- 2
Adding more stabiliser on top of stabilised tablets
A tablet adds cyanuric acid. It does not remove it. The UK Pool Store sheet prints about 30–50 ppm, with dilution as the way down. Extra stabiliser on top of a stabilised puck is a separate dose you did not need to copy from another tub.
- 3
Leaving tablets in a skimmer with the pump off
A floater is not a filter. One Deep Blue review warns against tablets left in the skimmer when the pump is off, after a large tablet lasted about 36 hours with the pump running. Use a feeder only for the chemical it was built for. Trust multifunction only when the bullets list the ingredients.
What to weigh up
Chemistry named on the listing
HighMultifunction, in this set, means the listing states stabilised chlorine plus a clarifier and an algaecide. Relax, the Deep Blue 20 g tub, and the Deep Blue 200 g multifunction tub do that. Stabilised means chlorine plus cyanuric acid, without those extras in the puck. ChlorineXpress describes slow-dissolving stabilised chlorine with cyanuric acid and does not list a clarifier.
Tablet size and where it goes
High200 g, also called 3 inch on the Relax highlight, is a palm-sized puck for a pool feeder. 20 g is the Deep Blue hot-tub size. 1 inch is the Bulla kit. SINPY is a small-tablet kit with a 5 inch floater. A 200 g puck is the wrong object for many hot tubs and paddling pools. Reviews of the Deep Blue stabilised tablets say they are palm-sized and hard to fit in a small dispenser. The feeder has to match the chemical. ChlorineXpress names a floating dispenser, a skimmer, or an automatic feeder.
Which option suits you?
Three typical situations, each with a recommendation from this comparison.
Hot tub or spa
Reviewers in this file use the Deep Blue 20 g tablets in hot tubs. A heavier 200 g bucket is the wrong object for many tubs. The unit-count field says 1.0 count against a 5 kg weight.
First weekend with an inflatable
The SINPY kit puts a 5 inch floater in the box at about £12.99. The title, the unit count, and the item weight do not agree, and the chemistry is not stated. Weigh the fill when the parcel arrives.
Common questions about chlorine tablets for pools
Which chlorine tablets for pools are the top pick on this page?
The top pick is the Relax 5 kg tub, 25 tablets of 200 g, at about £26.99. The title, the unit count, and the item weight agree on 5 kg. The highlight names trichloroisocyanuric acid, and the bullets add stabiliser, algaecide, and clarifier. It shows 4.6 from 264 amazon.co.uk reviews, the largest file here. No floater is included, and one review reports split blocks and chlorine dust. It fits an outdoor pool if you already own a dispenser or a skimmer and you will open the tub.
Which listing is the best value?
The best value is the Deep Blue 5 kg tub of 20 g multifunction tablets at about £21.98. It is the lowest price among the agreed 5 kg listings at 4.3 or above with at least 100 reviews. It shows 4.6 from 130 reviews, mostly from hot-tub users, and it states stabiliser, a clarifier, and an algaecide. The chlorine compound is not named, no dose is printed, and the unit count says 1.0 count. It is a poor match for a pool feeder built for a 200 g puck.
How much do chlorine tablets for pools cost?
On this amazon.co.uk capture, not a live check, the kits are about £12.99 and about £16.99. The 5 kg tubs whose title and weight agree run from about £21.98 to about £28.23, about £4.40 to £5.65 per kg. The Deep Blue stabilised listing at about £31.49 cannot sit on that per-kilo scale until the 1 kg versus 5 kg conflict is settled. swimmingpoolchemicals.co.uk listed 5 kg of 200 g stabilised tablets at £30.99 and 5 kg of 20 g multifunction tablets at £42.99. Those are that shop’s prices, not amazon.
Should I buy multifunction or stabilised tablets?
Multifunction listings here state stabilised chlorine plus a clarifier and an algaecide. That is Relax and both Deep Blue multifunction tubs. Stabilised listings are chlorine plus cyanuric acid, without those extras in the puck. ChlorineXpress and Deep Blue B0CWPDBMK3 sit there. Bulla puts multifunction in the title and does not list the ingredients. Only Relax names trichloroisocyanuric acid. If the bullets do not name the extras, treat multifunction as a title, not a formula.
Where should a chlorine tablet go?
Put the tablet only in a skimmer, floater, or feeder built for that chemical. A floater is not a filter. Do not leave tablets in a skimmer while the pump is off. The Deep Blue 200 g multifunction listing names a skimmer, a dosing chamber, or a floater. ChlorineXpress names a floating dispenser, a skimmer, or an automatic feeder. Relax does not say. A pool chlorinator is the separate comparison for the feeder, and it does not replace the dose printed on the tub you bought.
How should chlorinated tablets be stored?
PWTAG technical note 68 says keep chlorinated isocyanurates cool, below 30°C, closed, and dry, and never mix them with calcium hypochlorite. The Health and Safety Executive points operators of managed pools to the PWTAG Code of Practice. That is not a dose for a garden pool. Great Britain uses GB BPR for biocides. Northern Ireland uses EU BPR. Follow the label on your tub, and do not copy one listing’s gallon dose onto a different tablet.
Can I use a 200 g tablet in a hot tub or a paddling pool?
A 200 g puck is the wrong object for many hot tubs and paddling pools. The hot-tub size in this set is the Deep Blue 20 g tablet. The kits are SINPY, with a 5 inch floater at about £12.99, and Bulla, with 1 inch tablets at about £16.99. Both disagree on weight, so weigh the parcel. Empty a paddling pool after use. Children can drown in very shallow water.
What if the pack weight does not match the title?
Do not calculate a price per kilo until the figures agree. Deep Blue stabilised shows 5 kg in the title and 1 kg in the weight and the model. This page does not pick one. SINPY shows 100 g, 220 g, and 180 g. Bulla shows 1 lb, 500 g, and 670 g. Weigh the parcel when the title and the weight disagree.
Our verdict
The top pick is the Relax 5 kg multifunction tub at about £26.99. It is the only listing here that names trichloroisocyanuric acid, the title and the weight agree on 5 kg, and it shows 4.6 from 264 reviews. You still need a dispenser or a skimmer you already own, and you should open the tub for dust. The best value is the Deep Blue 20 g tub at about £21.98 when you want that small tablet and a review file of this size, not a slow 200 g puck.
Best value
View offer
Deep Blue 5 kg 20 g multifunction tablets
Lowest price among agreed 5 kg listings at 4.3 or above with at least 100 reviews, at about £21.98.
Editorial
Editor
DIY & tools
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Updated: 16.10.2026
8 sources checked
Guides to chlorine tablets for pools
Guides on what to look for, how to use a product, and common mistakes.
Chlorine tablets pool buying guideChemistry, tablet size, and a pack whose weight agrees with the title.Best chlorine tablets for a poolWho each kept listing is for, and who should skip it.How to use chlorine tabletsFeeder, test, cap on, and when to stop if the label is missing.Multifunction vs stabilised tabletsOne chemistry choice, without also deciding 20 g versus 200 g.Chlorine tablets for a small poolWhether any tablet here belongs in a small or paddling pool.
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Sources
Public UK sources listed in the research digest. Listing prices, stars, and review counts are from the amazon.co.uk capture dated 15 October 2026, not a live re-check.
- HSE — Swimming pool safety management (retrieved 15 October 2026)
- HSE SR9 — Safe use of pool biocides (retrieved 15 October 2026)
- HSE — Biocides regulations (retrieved 15 October 2026)
- HSE — GB CLP classification and labelling (retrieved 15 October 2026)
- PWTAG Code of Practice (retrieved 15 October 2026)
- PWTAG TN68 — Handling and storage of pool chemicals (retrieved 15 October 2026)
- UK Pool Store — What is cyanuric acid (retrieved 15 October 2026)
- Swimming Pool Chemicals — Chlorine tablets (retrieved 15 October 2026)
This page contains affiliate links to amazon.co.uk with the tag pcuk26-21. If you buy through them, we may earn a commission at no extra cost to you. Prices, stars, and review counts are the UK listing lines from the 15 October 2026 capture. We did not run a lab test.