Seachem Ammonia Alert
Ammonia Alert is an innovative colour device for continuously detecting and monitoring toxic free ammonia. 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.
Marine or freshwater use.