A maintenance dose through Hong Kong's hot, humid season stops algae before it starts — and after a shock treatment, algaecide is what keeps the green from coming back.
Algaecide is insurance, not a rescue. A regular maintenance dose stops algae establishing through Hong Kong's hot, humid season — and after a green pool has been shock-chlorinated, a follow-up dose stops regrowth while the filter clears up. Chlorine kills the bloom; algaecide keeps it from coming back.
A liquid concentrate that makes pool water hostile to algae. The common families are quaternary ammonium ("quat") algaecides — effective, economical, but surfactant-based and so prone to foaming where water is agitated — and polymer types, which are non-foaming and persist longer in the water at a higher cost per dose. Both work alongside chlorine, not instead of it: chlorine remains the sanitiser, while the algaecide suppresses the algae that would otherwise take hold whenever chlorine dips.
In Hong Kong that matters more than in most places. The hot, humid season is algae season: warm water, intense sun and busy pools give algae everything it wants, and an idle or covered pool — a clubhouse closed for works, a pool shut through a typhoon — blooms fastest of all, because still water with fading chlorine is an open invitation.
| Form | Liquid concentrate |
| Chemistry | Quaternary ammonium (quat) and polymer types — foaming vs non-foaming matched to the pool, confirmed on quotation |
| Formats | Pack sizes confirmed on enquiry |
| Best for | Preventive weekly dosing through the warm season, and regrowth control after shock treatment |
| Price | Quoted on enquiry — we reply within one working day |
As prevention: a small routine dose — typically weekly through the warm months — added with the pump running so it circulates fully. Keep chlorine and pH in their normal bands too; algaecide backs up good chlorination, it doesn't replace it. The dosing calculator gives your pool volume, and the water balance guide covers the chemistry that decides whether algae gets a foothold at all.
As treatment: algaecide is step two, not step one. A green pool is first killed with a chlorine shock — see calcium hypochlorite for that step — then, once chlorine has fallen back into its normal band, the algaecide dose goes in to stop regrowth while filtration and vacuuming remove the dead material. Skip the follow-up and the pool that went green once tends to go green again within weeks.
Safety. Algaecide concentrates are irritants — avoid skin and eye contact and handle with gloves. Never mix algaecide with chlorine or any other pool chemical, and never pre-mix products in the same bucket: dose each chemical to the pool separately. Store cool, dry and sealed, away from other chemicals and out of reach of children. Safety data sheets are available on request: see the SDS library.
Prices are quoted on enquiry — we reply within one working day. Tell us whether the pool has water features or spa jets and we'll recommend a foaming or non-foaming type. Delivery across Hong Kong; ask about a standing delivery for estates and operators.
As prevention, a small routine dose — typically weekly through Hong Kong's warm months — added with the pump running so it circulates fully, with chlorine and pH kept in their normal bands. As treatment, algaecide goes in once, after the chlorine shock has killed the bloom and chlorine has fallen back into its normal band, to stop regrowth while filtration removes the dead material.
No. Once algae has bloomed, the kill step is chlorine — a shock dose takes the pool from green to a dead grey-white. Algaecide is the follow-up: dosed after the shock, once chlorine has settled back into its normal band, it stops the survivors re-establishing while the filter clears the debris. Used alone against an established bloom, algaecide is slow and usually disappointing.
Quaternary ammonium (quat) algaecides are effective and economical, but being surfactants they can foam — noticeably so in pools with water features, spa jets or heavy splashing. Polymer-based algaecides are non-foaming and longer-lasting in the water, at a higher cost per dose. We recommend the type to suit the pool, so tell us about yours.
Through the hot, humid months — roughly May to October — when warm water, strong sunlight and heavy bather loads all favour algae. Idle and covered pools are hit hardest: still, poorly circulated water blooms fastest, which is why pools so often turn green during a closure or straight after a typhoon shutdown. A routine maintenance dose of algaecide alongside normal chlorination is cheap insurance through the season.
Send us the pool size and a photo — we'll tell you the shock dose, the follow-up and what to order. No obligation.