Ammonia Alert — Continuous Ammonia Sensor 1 Year | Seachem

The Seachem Ammonia Alert is an innovative color-changing sensor that continuously detects and monitors toxic free ammonia in both freshwater and saltwater aquariums. The sensor reversibly changes color—from yellow (safe) to green (alert) to blue (toxic)—depending on the ammonia concentration. No test kits, chemicals, or procedures are required. It detects less than 0.05 mg/L of free ammonia and lasts for more than a year, over nine times longer than competing products.

Main advantages

• Continuous 24/7 monitoring of toxic free ammonia — 15-minute response time
• Detects less than 0.05 mg/L of free ammonia — alerts before any sign of stress
• Lasts for more than a year — 9 times longer than competing products (4–6 weeks)
• Compact size 1.5" x 2.5" — discreet and unobstructive in the aquarium
• No test kit, chemical or procedure required — instant visual reading
• Suitable for use in both saltwater and freshwater

Sensor reading

• Yellow: SAFE — no free ammonia detected
• Pale green: ALERT — 0.05 mg/L of free ammonia. Tolerated for 3 to 5 days. Monitor and consider a water change.
• Grey/green: ALARM — 0.2 mg/L of free ammonia. Tolerated for 1 to 3 days. Perform a water change promptly.
• Blue: TOXIC — 0.5 mg/L of free ammonia. Immediate danger. Action required immediately.

Use in reef and marine aquariums

Ammonia is the number one killer of aquarium fish. The Ammonia Alert specifically detects free ammonia (NH3, the toxic gaseous form), not ammonium (NH4+, the harmless ionized form). Conventional ammonia tests measure total ammonia (free + ionized), which can give misleading results. In saltwater at pH 8.3, 0.02 mg/L of free ammonia corresponds to 0.25 mg/L of total ammonia. Place the sensor visibly in the aquarium or sump for quick readings at any time.

Instructions for use

• Place the sensor visibly in the aquarium or filter — use the included suction cup
• A dry sensor may have a greenish tint — this is normal. Balancing may take a few days.
• Read under natural light or daylight-simulating light for maximum sensitivity
• Red light minimizes green and blue hues, reducing apparent sensitivity
• To check if it's working, briefly hold the sensor over an open bottle containing ammonia — the color should develop quickly.

Compatible with Seachem Prime

The Ammonia Alert detects free ammonia before the Prime unit has complexed it. Once the Prime unit has complexed the ammonia (rendering it non-toxic), the sensor no longer detects it—which makes sense since the ammonia is no longer hazardous. To determine the total ammonia level (free, ionized, and complexed), use a total ammonia test kit.

Manufacturer's precautions

• Not recommended for use at acidic pH (below 7.0) — at acidic pH, free ammonia cannot exist chemically.
• Do not touch the sensor with your fingers — skin oils can damage it.
• Do not use bleach, soap, detergents, or hard objects to clean the sensor.
• Some dye-based medications can discolor the sensor
• Sensitivity improves with age if the sensor remains moist — drying does not permanently damage the unit
• For emergency treatment of ammonia, use Seachem AmGuard.

Why choose Ammonia Alert from ReefSolution?

Ammonia Alert is an essential monitoring tool for any marine or reef aquarium, especially during cycling, when adding new fish, or during extended absences. Combine it with Seachem Prime to neutralize ammonia and Seachem Stability to establish the biofilter. For emergency treatment, keep Seachem AmGuard on hand.

Frequently Asked Questions

Does the Ammonia Alert work with Seachem Prime?

Yes. The sensor detects free ammonia before Prime binds it. Once Prime has rendered the ammonia non-toxic, the sensor no longer detects it, confirming that the treatment has worked. For the total level, use a conventional ammonia test.

Why isn't my Ammonia Alert changing color?

The Ammonia Alert detects only free ammonia (NH3), not ammonium (NH4+). At acidic pH (below 7.0), free ammonia cannot exist. In seawater at pH 8.3, the sensor is most sensitive. A dry sensor may take a few days to equilibrate. Check its operation by holding it over a cleaning solution containing ammonia.

How long does the Ammonia Alert last?

Over a year of continuous use, which is 9 times longer than competing products that last 4 to 6 weeks. Depletion is indicated by a visible fading of the sensor's color.