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pH, chlorine, bromine, floc and algaecide — each spa-shop tub matched to the salt on the label.
Teardowns
19
Typical saving
66%
Steepest gap
Hardness Plus (Calcium Increaser)
Spa-shop pH Plus, pH Minus, hardness and chlorine are soda ash, dry acid, calcium chloride, TCCA tablets or dichlor granules. Dose from a test kit, not a marketing scoop.
Cyanuric acid (stabiliser) accumulates from TCCA and dichlor. Test it. Over-stabilised water will not sanitise no matter how many branded tablets you add. Cal-hypo shock does not add CYA.
Keep oxidisers away from acids in the store cupboard. Pool chemicals are still COSHH substances when they come in a 1 kg tub.
This hub currently covers 19 pool & spa teardowns. Typical saving versus a branded pack is about 66% per working litre. The steepest gap today is Fi-Clor Hardness Plus (Calcium Increaser) at 94%. Snapshot retail prices start around £9.99 — live shop listings move.
Pool guide
Pool and spa basics: pH, chlorine and cyanuric acid without the brand kit
What Clearwater-style pH Plus, pH Minus, chlorine and CYA actually are — soda ash, dry acid, TCCA and stabiliser — with links to DupeStack teardowns.
Pool guide
Pool shock, bromine, floc and algaecide — not the same tub
Cal-hypo shock, dichlor granules, MPS oxidiser, BCDMH bromine, alum floc, copper algicide and thiosulphate reducer are different salts. Match the job before you buy a spa-shop tub.
Pool guide
Phosphate remover and polyquat — not a shock, and not copper
Lanthanum chloride drops phosphate. A polymeric quat is a copper-free algicide. Neither replaces trichlor, dichlor or cal-hypo, and neither is alum floc.
Pool guide
PHMB and bromine pool care: chlorine-free sanitising decoded
How polyhexanide (PHMB) and sodium bromide work as chlorine-free pool sanitisers — activation chemistry, compatibility rules, and links to DupeStack teardowns.
Pool & spa
Clearwater
pH Plus is dense soda ash — 99% sodium carbonate, CAS 497-19-8. Pool-shop packaging turns a £2.70/kg commodity into an £11.50/kg ritual.
Pool & spa
Clearwater
pH Minus is dry acid — sodium bisulphate. Pool retail is a small tub; chemical suppliers sell it in 5 kg lots for a third of the per-kilo price.
Pool & spa
Clearwater
The tablet is 90% TCCA — the same stabilised chlorine used in bulk 200 g pucks. ‘Multifunction’ is a pinch of clarifier and a lot of packaging. Buy TCCA, dose from an SDS, and keep cyanuric acid in range.
Pool & spa
Clearwater
Standard baking soda sold at a 1,200% retail markup under spa branding.
Pool & spa
Fi-Clor
Repackaged de-icing and industrial desiccating salt marked up tenfold.
Pool & spa
Clearwater
100% cyanuric acid in a 1 kg spa tub. The same granules sell in 5 kg lots at a fraction of the per-kilo price. Dose to a test kit (typically 30–50 ppm CYA), not a marketing scoop.
Pool & spa
Lo-Chlor
A 15% phosphonate in a 1 litre bottle. Industrial 60% HEDP is the same sequestering chemistry; 50 ml of 60% in 10,000 litres is a typical maintenance dose.
Pool & spa
Fi-Clor
This is not TCCA and it is not bottle bleach. Cal-hypo is the same oxidiser sold to commercial pools in 5–10 kg kegs. A 2.5 kg spa tub is a small pour from that keg.
Pool & spa
Clearwater
‘Non-chlorine shock’ is Oxone-type MPS — the same triple salt used in bulk oxidisers. A 1 kg spa tub is a markup on a 5 kg bucket. It oxidises organics; it is not a sanitiser on its own.
Pool & spa
Clearwater
Spa bromine tablets are BCDMH. The 1 kg tub is the same 20 g pucks sold in 5 kg tubs to holiday-park plant rooms. You still need a floater and a test kit.
Pool & spa
HTH / Fi-Clor
Floc is alum. Aluminium sulphate is a water-works coagulant sold in 5–25 kg sacks. A 1 kg spa tub is a labelled scoop from that sack. Not a sand-filter magic potion, and not polyquat. Vacuum to waste after it drops.
Pool & spa
Fi-Clor / Swimfresh
The spa-shop ‘chlorine reducer’ is photographer’s hypo: sodium thiosulphate. A 2.5 kg tub is a small bag of the 5 kg photo/pool salt. Dose from a test kit. Too much and you will have no sanitiser left.
Pool & spa
Lo-Chlor
Not BAC (Clearwater algaecide is a quat — we skip that duplicate). Lo-Chlor copper is copper sulphate in acidified water — a classic metal algicide. Bulk CuSO4·5H2O crystals dissolve to the same copper donor without the pool-shop markup.
Pool & spa
Clearwater
Clearwater’s 1 kg spa granules are sodium dichloroisocyanurate dihydrate (troclosene sodium, CAS 51580-86-0) — dichlor, not TCCA tablets and not Fi-Clor Superfast cal-hypo. About 2 g per 1,000 L raises free chlorine by 1 ppm; 10 g/m³ is a typical ~5 ppm shock. A 5 kg trade sack is the same salt. Dichlor adds cyanuric acid, unlike cal-hypo.
Pool & spa
Blue Horizons
This is a polymer clarifier, not floc. Complete Pool Controls’ Ultimate Water Clarifier SDS lists an aqueous solution of polydiallyldimethylammonium chloride (polyDADMAC, CAS 26062-79-3) at 10–30%. It polishes fines into the filter. Aluminium sulphate floc drops a blanket you vacuum to waste. A 5 L trade jerry of the same 20% band is the same polymer without the 1 L spa-shop tax.
Pool & spa
Lo-Chlor
Phosphate remover is lanthanum chloride, not a clarifier and not an algaecide. Lo-Chlor’s UK SDS (Port Talbot) lists lanthanum chloride hydrate (CAS 20211-76-1) at 10–30%. Swimming Pool Chemicals lists the same liquid at £23.99 for 1 litre and £89.99 for 5 litres — about £18 a litre in the jerry, a quarter off the small bottle. It does not sanitise.
Pool & spa
Fi-Clor
Copper-free pool algicide is a polymeric quat, not copper sulphate and not BAC. The Fi-Clor SDS lists polymerised quaternary ammonium (CAS 25988-97-0) at 10–25%, plus etidronic acid (CAS 2809-21-4) at 2.5–10%. A 3 litre bottle is about £37. A 5 litre trade jerry of polyquat algaecide is about £31 — roughly half the price per litre, if the jerry’s SDS is in the same strength band.
Pool & spa
Lonza
Bromine activator is pure sodium bromide (NaBr, CAS 7647-15-6). The pool and spa trade sells it in branded 2 kg tubs; lab and photo suppliers sell the same technical-grade sodium bromide in 5 kg bags. There is no magic activation chemistry in the tub — you pay for the label and the small pack.
Pool & spa
Baquacil
Baquacil sanitiser is 20% PHMB (polyhexanide, CAS 32289-58-0) in water. PHMB is a broad-spectrum polymeric biguanide used in contact lens solution, wound irrigation and industrial biocides. The pool trade charges a heavy premium per litre; the same molecule is available as a 20% pool-grade solution from aquatics distributors at roughly half the retail price per litre.