Water test
kit formats.

§01 — Three formats.

Water testing products for ornamental ponds are sold in three formats: liquid reagent kits, dry test strips, and digital meters. Each format measures one or more parameters by a different physical mechanism and at a different per-test cost.

This article describes how the formats work as products. It does not describe target ranges or interpretation; consult the kit's own printed reference card or the manufacturer's documentation.

§02 — Liquid reagent kits.

A liquid reagent kit consists of small numbered dropper bottles, a glass test tube, and a printed colour-comparison card. Performing a test involves:

1. Filling the test tube to a marked line with pond water.
2. Adding a stated number of drops of one or more reagent solutions.
3. Capping and inverting the tube to mix.
4. Holding the tube next to the comparison card and reading the matching colour shade.

Manufacturer documentation cites approximately 50–100 individual tests per parameter from a typical bottle of reagent. Reagents carry expiration dates, and storing the kit out of direct sunlight is recommended.

The most widely distributed liquid kit for pond use is the API Pond Master Test Kit, which measures pH, ammonia, nitrite, and phosphate in a single boxed set.

§03 — Dry test strips.

Test strips are paper or plastic strips with chemical-impregnated pads that change colour when dipped in water. A typical pond-use strip measures four to six parameters in one dip, with results read at a stated number of seconds against a printed colour key.

Strip-format kits are typically less expensive per test than reagent kits but are widely regarded by manufacturer documentation as a screening rather than precision tool. Strip results are sensitive to dip duration, ambient lighting at read-time, and the strip's exposure to humidity in storage.

§04 — Digital meters.

Digital meters measure parameters electrochemically rather than chemically. Common meter types in the pond market include:

• pH meters — a glass electrode probe measuring hydrogen-ion concentration.
• TDS meters — total dissolved solids, measured via electrical conductivity.
• EC meters — electrical conductivity directly.
• Salinity meters — typically a calibrated TDS reading scaled for sodium chloride.

Meters require calibration with reference solutions before first use and at intervals stated by the manufacturer. Probes are consumables — manufacturer documentation typically cites a one- to two-year service life depending on usage frequency.

§05 — Parameters commonly measured.

Across all three formats, the parameters typically measured for ornamental ponds are:

• pH — acidity / alkalinity, on a 0–14 scale.
• Ammonia (NH₃ / NH₄⁺) — total ammonia nitrogen.
• Nitrite (NO₂⁻) — intermediate of biological filtration.
• Nitrate (NO₃⁻) — end product of nitrification.
• KH (carbonate hardness) — buffering capacity.
• GH (general hardness) — total dissolved minerals.
• Phosphate (PO₄³⁻) — sometimes included in pond-specific kits.