Technical education for Hong Kong building owners and engineers. Researched and referenced — every article answers one real question and cites its primary sources.
Legionella and the EMSD rules, water chemistry, tower operation, the economics of treatment, pool care and reference tools. Pick a topic to filter the articles, or read them all.
Why a HK$100k dosing system looks expensive and a HK$5m pipe replacement does not. With an NPV calculator.
Where it comes from, why cooling towers are the classic source, and what genuinely controls it.
Why the same dose of chlorine works at pH 7 and fails at pH 8.5 — and which biocides do not care.
Why pipework rots from the inside, the forms it takes, and what treatment is really doing.
What the EMSD Code of Practice requires, and where the 10 and 1,000 cfu/mL thresholds sit.
Cleaning, desludging and disinfection frequency for Hong Kong buildings.
The water quality table, the Legionella action ladder, cleaning frequency and the record-keeping rules — from the actual 2023 Code.
Why your chlorine residual reads fine and your bacteria counts do not, and why Legionella hides inside amoebae.
The number that decides how much water your tower wastes — and why you cannot simply turn it up. With a calculator.
The most widely used number in cooling water, the five things it cannot see, and a live LSI calculator.
Why pH 7.2–7.8 matters, what alkalinity and hardness actually do, and the target ranges that stop chlorine being wasted.
Trichlor tablets or sodium hypochlorite? Strengths, pH effects, stabiliser build-up and which fits your pool.
What pool stabiliser does, why it accumulates with tablet chlorine, and why dilution is the practical fix.
A strong chlorine smell means too little free chlorine, not too much. Chloramines and breakpoint chlorination, explained.
Seven things to demand from any Hong Kong water treatment contractor, the questions to ask, and how to compare quotations.
Why stagnant warm water breeds Legionella, and the restart sequence — inspect, clean, disinfect, verify, sample, document.
Every published EMSD cooling tower Legionella sampling round in one table, with a plain-English reading of the numbers.
40 water treatment terms with Traditional Chinese equivalents and plain-English definitions, A–Z.
The printable one-page duty-holder checklist: the three Legionella bands, the recurring duties, and a monthly tick grid for the plant room.
Who needs an FEHD swimming pool licence in Hong Kong, the water-quality and testing conditions attached, and what to keep on file.
How storms contaminate roof tanks, the warning signs, and the inspect → test → disinfect → re-test → document decision path.
Ask us — if it is a good question, we will research it and publish the answer.