Ammonia Aqua Sensor

Ammonia Aqua Sensor

Pacific Sentry’s ammonia aqua sensor enables visual monitoring of toxic ammonia (NH3) in aquaria water on a continuous basis. Simply attach it in a visible location where it can be left and easily viewed, with the sensor pad completely immersed. With initial use, wait about 15 minutes for the sensor to hydrate before making first reading. Thereafter they respond quickly (1-5 minutes) to NH3. To get a measurement, simply match the sensor’s color to the color-gradient indicator chart to readout the NH3 concentration.

“Even at levels of 0.1 ppm, ammonia can be lethal. Is your aquatic environment at risk?”

Key Features
  • Continuous monitoring – 24/7, the ammonia level can be determined with a quick glance.
  • Fresh & saltwater – compatible in any aquatic environment.
  • Long lasting – up to 1 year.
  • Ammonia detection – NH3 is directly measured, which is the toxic concern, rather than the ammonium (NH4+) ions in water commonly detected by other tests as an indirect indicator of the potential risk of NH3 poisoning.
  • Unaffected by chemicals – ammonia stabilizers and other chemical agents won’t affect the performance of the sensor.
  • NO chemicals, test kits, sampling of water, or procedures are needed.
  • Highest NH3 sensitivity – capable of detecting extremely low concentrations (0.005 ppm), this sensor offers more protection of aquatic systems.  Earlier indications of increasing levels enable better management of water quality, more time for corrective action, and less risk of exposures to injurious NH3 levels.
  • Larger sensor – measures 2.1″ x 3.4″, making it much easier to view from a distance.
Discussion of NH3 & NH4+

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.

Sensor Respones

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 Viewing

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.

Ammonia Sensor Sensitivity

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.

Sensor Usage Life

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.

Sensor Care

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.

Get to Know Your System

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.

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Ordering Information

Buy your sensors online by clicking the “add to cart” button on the Products page or call (425)-229-9701 and talk directly to a representative to place an order. Custom fabrication requests are also welcomed; call or email for details. We will gladly work with you to design the best solution that meets your needs.

Shipping & Handling
in the United States

Products will be shipped within 2-4 business days. Ground shipping usually takes 3-5 days depending on shipping destination.

International Shipping
(Including Canada)

International shipping and handling depends on the specific country. Please email Customer Service at with your shipping address, product of interest and desired quantity. A shipping estimate will then be provided.

Our Return Policy

If you are not satisfied with our product for any reason, please return it within 14 days of receipt for full refund.

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