About

A plain-language reference on water treatment, written for people who have to specify or operate a system rather than sell one.

Most material available on filtration is produced by companies selling filtration. That material is often technically accurate and still misleading, because it compares its own method at its best against alternatives at their worst.

These pages take the opposite approach: state what each method does badly as well as what it does well, and name the operating conditions where the comparison changes.

Nothing here is a design document. Real systems are specified against real water analyses and local regulation, by people who carry the liability for getting it right.

Where these pages state a number, it is a typical operating range rather than a specification. Real water varies by season, by source and sometimes by hour, and any figure quoted without the conditions attached is a marketing claim rather than an engineering one.