Unlike most ammonia testing systems, Pacific Sentry’s ammonia aqua sensor measures only the toxic form or free-ammonia (NH3) in aquatic environments. It is the best direct indicator of the toxicity your pond life is subjected to. Ammonia (NH3), the toxic form, is normally in far lower concentrations than the much less harmful Ammonium ion (NH4+). The ratio of NH3 to NH4+ changes with temperature and pH; a rise in pH or water temperature causes increasing amounts of toxic NH3 (See Total Ammonia Calculation for further information).

Therefore, in addition to the ammonia, it is valuable to know the pH of the water and its ammonium NH4+ content. It’s important towards fully understanding your aquatic system’s potential risk level. Realize that a sudden rise in pH can cause a significant conversion of NH4+ into NH3 resulting in toxic levels. With an ammonia and pH measurement, one can derive the water’s Ammonium content, as well as Total Ammonia (NH3 plus NH4+).

Note: most other test kits actually measure Total Ammonium, even though they are routinely identified as ammonia tests.

Little if any ammonia is found in a healthy system and the sensor will look typically light-yellow, similar to the card background color. Watch for rising ammonia. Exposure to increasing levels changes the sensor to shades of green, grey, and then purple. When ammonia decreases, the sensor color accordingly reverts back to yellow, but the color change is slower. A sensor response of grey or purple color indicates potentially hazardous ammonia levels. Even 0.01 ppm, (light green) can be lethal for some organisms. Take appropriate action to reduce ammonia and alleviate the toxic risk.

Sensor color perception and matching is influenced by the nature of the light used for viewing. Lighting for aquaria have different spectral outputs. We recommend viewing under fluorescent lighting.

Pacific Sentry’s ammonia sensor is designed to be highly sensitive to ammonia in the low ppb (parts per billion) range. It can detect ammonia (NH3) at 0.005 ppm. This provides the earliest possible indication of ammonia increasing in your system; thus the highest level of protection, lowest risk of toxic injury, and a greater margin of safety for taking corrective measures.

Pacific Sentry’s sensor can show the presence of ammonia when other products may not. Do not confuse the sensor’s ammonia indication with other test products that measure Total Ammonia. They will have much higher values in the ppm range.

The useful lifetime of the sensors can be influenced by a number of factors that vary from system to system. Though unable to predict for your particular conditions, it should be useful for up to a year, before needing replacement.

Gradual fading of sensor colors over time is to be expected. Exposure to direct intense lighting, for instance, can influence this, and is best avoided. Sensors can be taken out of water and dried without harm. However, they will need to be re-hydrated.

Avoid damaging the sensor by fingers, fish, or other types of physical contact. Touching with fingers may discolor the sensor and affect performance. Sensors can be taken out of water and even dried without harm. However, they need time to re-hydrate again when returned to use.

You will quickly become familiar with the sensor’s typical color for your system’s water quality. With a glance, you should be able to identify its status, whether it is in normal range, or if changes are occurring. Rising ammonia indicates changes in your water quality; some environmental aspect is no longer in ideal balance. When setting up new ponds, or with large water changes, an increase in ammonia is expected. The system is undergoing conditioning. As the environment develops proper balance, ammonia declines.

Disruptive changes in ideal water balance include: increasing the quantity of fish, overfeeding, reduced efficiency of the filter, changes in pH or salt content, water treatments, or anything affecting the balance of important bacteria.

When the sensor detects rising ammonia, giving warning of potential toxic risk, consult your local specialist or seek other professional advice for corrective action.