Seachem Lil Alert Mates -Ruby barb

Lil’ Alert Mates are innovative color devices for continuously detecting and monitoring toxic free ammonia. They work just like Ammmonia Alert but are designed to appeal to the young aquarist. A sensor changes reversibly from yellow to green to blue, relative to the ammonia concentration. No test kits, chemicals, or procedures are needed. The device detects less than 0.05 mg/L (ppm) free ammonia and alerts you to the #1 killer before any sign of stress. It lasts over a year and replacement sensors are available. Marine or freshwater use.
In the absence of free ammonia the unit will assume a yellow or faint yellow-green color. It is normal for the dry sensor to have a greenish hue. It may take up to a few days for a dry sensor to equilibrate with the water. No sampling of water, chemicals, or test procedures are required. The presence of the free ammonia is detectable continuously with a response time of about 15 minutes. Response to decreasing ammonia is slower, requiring about 4 hours to go from TOXIC to SAFE on removal of ammonia.