The Ammonia Test Kit measures total ammonia in aquarium water — that is, the sum of ammonia (NH₃, the toxic un-ionized form) plus ammonium (NH₄⁺, the ionized, relatively non-toxic form, though equilibrium depends on pH/temperature).

It does not separately distinguish NH₃ vs NH₄⁺ — you must calculate or infer the fraction of toxic NH₃ yourself, based on pH/temperature.

Ammonia and ammonium are substances which should be converted rapidly into nitrite followed by nitrate and nitrogen gas.

If this does not happen then the aquarium is not fully cycled or biological processes are not proceeding as they should.

The Salifert Ammonia test is very straightforward and measures the sum of toxic ammonia and ammonium in just a few minutes.

The kit can perform approx. 50 measurements and can detect 0.5 ppm of total ammonia easily.

A typical Salifert Ammonia Test Kit includes:

• Reagent bottles (several solutions)

• A test vial / glass tube

• Measuring syringes for adding precise volumes of reagent and water

• Instruction sheet / color chart

• Enough reagent to perform approximately 50 tests

Because reagent volumes per test are small, the kit overall fits in a compact package.

Measurement Range 

• The kit can detect as low as 0.5 ppm (mg/L) total ammonia reliably.

• The color chart allows readings at increments (e.g. 0, 0.5, 1.0, 2.0, etc.) — so for moderate to high ammonia levels you can estimate upward.

• In practical use, many aquarists consider 0.5 ppm “the floor” for confident detection; values below that may be hard to distinguish.

Instructions

1. Add sample water to a test vial.

2. Add a specific volume of reagent 1 (a buffer / conditioning agent).

3. Add reagent 2 (nitroprusside, or other color-forming agents) which reacts with ammonia to develop color.

4. Optionally add a third reagent to intensify or stabilize the color.

5. Mix, wait a specified reaction time (few minutes).

6. Compare the resulting color (usually yellow to green to blue/green) against the provided color chart under good lighting conditions.

The intensity of the color correlates with the concentration of total ammonia.

Because the reaction is for total ammonia, the test doesn’t differentiate ammonia vs ammonium — the equilibrium between NH₃ and NH₄⁺ depends on pH and temperature. To estimate the toxic (un-ionized) fraction, you need to know pH and temperature and use a formula or table.

Strengths:

• Many users report it gives consistent, repeatable results under proper conditions.

• The kit covers a useful detection floor (0.5 ppm) for general aquarium monitoring.

• It’s relatively simple to use, so it’s practical for routine checking.

Limitations:

• Lighting & reading conditions matter. Many hobbyists emphasize reading colors under diffused daylight (not direct sun or fluorescent glare) to reduce misinterpretation.

• Color discrimination error. At low concentrations, small color shifts can be subtle, so user judgment plays a role.

• Interfering substances. Presence of high levels of nitrates, nitrites, organics, or dye compounds might interfere (as with all colorimetric tests).

• pH / temperature effect. Because the kit measures total ammonia, without pH data you cannot know exactly how much is un-ionized ammonia (the more toxic form).

• Differences vs other kits. Some aquarists report that Salifert readings differ from those of other brands (Red Sea, API, etc.) — either higher or lower.

• When ammonia is very low (approaching zero), the test’s precision becomes poor.

Practical Use Tips 

• Always shake reagent bottles gently and ensure they are well mixed before use.

• Use clean test vials / syringes to avoid contamination.

• Make sure timing (waiting after reagent addition) is accurate — over- or under-waiting can skew results.

• Read under good, consistent lighting. Many users take the test outdoors in shade or under natural but diffuse light.

• Record pH and temperature at time of ammonia test, so you can estimate the fraction of un-ionized NH₃.

• If you get a value, compare it periodically (same tank, same method) to watch trends rather than relying on absolute single values.

• Discard reagents if they expire or if cloudiness / discoloration in reagent bottles appears.

Interpretation

• In a well-cycled, healthy aquarium, total ammonia should ideally read zero (or “undetectable”). Any detectable ammonia indicates that nitrification or filtration is not fully coping with the nitrogen load.

• If ammonia is present, conduct partial water changes, ensure your biofilter is healthy, reduce feeding, etc.

• Use trends over days (rising/falling) to assess tank stability and response to interventions.