Guides & resources.

The four methods that matter — strips, TDS pens, lab panels, and spectral scans — compared side-by-side.

A TDS pen measures conductivity — one number. Spectral sensing reads the molecular fingerprint, including organic load TDS can't see.

What to check yourself between annual lab tests — pH, hardness, TDS, iron, and organic load.

The six numbers that run your pool — pH, chlorine, alkalinity, hardness, CYA, organics — and how to read them in seconds.

Salt cells still make chlorine. Here is what shifts in your testing routine — salinity, CYA, pH drift, and cell health.

Refills, colour-matched fakes, and evaporated cork-sick bottles — the measurable signals that give them away.

The phenolic chemistry behind color, structure, and aging — and how to measure it from one drop.

When to trust a spectral sensor and when to send samples to ETS or a certified lab.