The gap these bottles fill
The basics guide is pH, alkalinity, TCCA and cyanuric acid. The shock guide is cal-hypo, dichlor, MPS, BCDMH bromine, alum, copper and thiosulphate. What those pages do not cover is phosphate, and a copper-free algicide that is actually a polymeric quat.
Cloudy water, a green tint and a ‘clarifier’ shelf are three different decisions. Test free chlorine (or bromine), pH and — if the algae keeps returning — phosphate. Then pick one molecule.
Phosphate remover is lanthanum chloride
Lo-Chlor Starver X is lanthanum chloride hydrate (CAS 20211-76-1 on the UK SDS, 10–30%). Some sheets list the anhydrous salt (CAS 10099-58-8) instead. Same rare-earth chloride, different water of hydration. It is not polyDADMAC and it is not alum.
The label rate is one litre to take up to 6 ppm of phosphate out of 50,000 litres — about 20 ml per cubic metre for that full drop. Add with the filter running. The water can cloud as lanthanum phosphate forms; backwash when the pressure rises. A 5 litre jerry of the same liquid is cheaper per litre than the 1 litre bottle. Laboratory lanthanum powder is not a pool dose.
Phosphate control starves algae. It does not oxidise them and it does not hold a residual. If phosphate is already low, more lanthanum will not clear a chlorine problem.
Copper-free algicide is polyquat, not copper
Fi-Clor Multi-Functional Algicide (copper-free) is a polymerised quaternary ammonium, CAS 25988-97-0, at 10–25% on the SDS, with etidronic acid (HEDP, CAS 2809-21-4) at 2.5–10%. The season rate on the bottle is 1.5 litres per 50,000 litres every six months — about 30 ml per cubic metre. The concentrate is strongly acidic. Do not mix it with chlorine in a bucket.
Lo-Chlor copper is a different algicide: copper sulphate, held around 0.5 ppm copper, and it stains if you overshoot. A trade 5 litre polyquat jerry can be about half the price per litre of the 3 litre Fi-Clor bottle, but only if its SDS is the same polymer in a similar strength band. A 60% technical polyquat is a different dilution. Read the jerry.
The HEDP in the Fi-Clor bottle is a sequestrant, the same family as Lo-Chlor No More Scale, at a lower share of the bottle. It is not a reason to skip a scale programme, and it is not the algicide.
Still not a sanitiser — trichlor, dichlor, cal-hypo, bromine
Slow outdoor chlorine is usually trichloroisocyanuric acid tablets (TCCA, CAS 87-90-1). They last, and they add cyanuric acid. Fast granules are often dichlor (NaDCC dihydrate, CAS 51580-86-0) — quick, near pH-neutral, and they also add CYA. Calcium hypochlorite shock (CAS 7778-54-3) is unstabilised and raises hardness. Hot-tub tablets labelled bromine are BCDMH (CAS 16079-88-2), not a chlorine puck and not sodium bromide with a pinch of dichlor.
Choose the sanitiser from the test kit and the existing shock and basics guides. Polyquat and lanthanum sit beside that residual. They do not replace it. MPS ‘non-chlorine shock’ is an oxidiser with no residual either — a different tub again.
Cloudy is not automatically phosphate
After a heavy bather load, oxidise first (dichlor or cal-hypo, not a phosphate bottle). Dead fines then either drop with alum (vacuum to waste) or polish on the filter with polyDADMAC. Phosphate remover is for a measured phosphate problem. Copper is for algae when you accept a metal residual. Polyquat is the copper-free algicide path.
One addition at a time, pump running, never a bucket of concentrates. The teardowns are pack maths for the salt on the SDS — not a plant-room manual.
FAQ
- Will a phosphate remover sanitise the pool?
- No. Lanthanum chloride precipitates phosphate so algae have less nutrient. It does not leave a chlorine or bromine residual. Keep the sanitiser in range — TCCA tablets, dichlor, cal-hypo or BCDMH, whichever the SDS in your hand actually is.
- Is Fi-Clor Multi-Functional Algicide a copper bottle?
- No. The SDS names a polymerised quaternary ammonium (CAS 25988-97-0) at 10–25%, plus some etidronic acid. Lo-Chlor copper is copper sulphate (CAS 7758-98-7). Different molecule, different stain risk. Do not stack them because both labels say algae.
- Can I use polyquat instead of trichlor tablets?
- No. Polyquat is an algicide, not a primary sanitiser. Trichlor (TCCA, CAS 87-90-1) is a slow chlorine donor that also adds cyanuric acid. Dichlor granules and cal-hypo shock are different chlorine salts again. Pick the sanitiser from a test kit, then add phosphate control or a copper-free algicide as a separate job.
More pool & spa guides
Related teardowns
Live stacks this guide points at — mix maths and DIY affiliate links on each page.
Pool & spa
Starver X Phosphate Remover
Lo-Chlor
- Retail pack
- £23.991 litre
- Raw active
- Lanthanum chloride hydrate solution (Starver X, 5 litre)20211-76-1
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
Multi-Functional Algicide
Fi-Clor
- Retail pack
- £36.993 litres
- Raw active
- Sodium bromide (bromine bank activating salt)7647-15-6
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
Copper Algaecide
Lo-Chlor
- Retail pack
- £14.991 litre
- Raw active
- Copper sulphate pentahydrate (CuSO4·5H2O)7758-98-7
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
No More Scale Inhibitor
Lo-Chlor
- Retail pack
- £24.501 litre
- Raw active
- HEDP 60% phosphonate concentrate2809-21-4
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
Ultimate Water Clarifier Concentrate
Blue Horizons
- Retail pack
- £20.501 litre
- Raw active
- PolyDADMAC 20% aqueous pool clarifier26062-79-3
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
Rapidfloc / Granular Floc
HTH / Fi-Clor
- Retail pack
- £12.991 kg tub
- Raw active
- Aluminium sulphate (alum) crystals 17%10043-01-3
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
Clearwater Multifunction Chlorine Tablets
Clearwater
- Retail pack
- £42.005 kg
- Raw active
- TCCA 90% chlorine tablets (200 g)87-90-1
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
Stabilised Chlorine Granules
Clearwater
- Retail pack
- £12.991 kg tub
- Raw active
- Sodium dichloroisocyanurate dihydrate (NaDCC / dichlor, ~55% available Cl)51580-86-0
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
Superfast Shock Chlorine Granules
Fi-Clor
- Retail pack
- £34.002.5 kg tub
- Raw active
- Calcium hypochlorite granules 65–70%7778-54-3
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
Bromine Tablets
Clearwater
- Retail pack
- £24.001 kg tub
- Raw active
- BCDMH bromine tablets 20 g16079-88-2
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.
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