Ammonia Alert - 1 year supply - Freshwater & MarinepH Alert - 1 year supply - FreshwaterAmmonia Alert® is an innovative color 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.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.Ammonia Alert® lasts over 9 times as long as competing products (over a year compared to 4-6 weeks). Ammonia Alert® is also almost half the size of competing products (1.5\" x 2.5\"). It\'s small, clear, and unobtrusive, so it won\'t detract from the view of your aquarium.pH Alert® is a unique color device designed to be placed in the aquarium or filter and monitor pH continuously. A sensor changes color reversibly to alert you shifts to in pH levels between 5.4 and 8.0. No tests, no strips, just constant readings. Freshwater Only.pH Alert® lasts up to 4 times as long as competing products. pH Alert® is also almost half the size of competing products (1.5\" x 2.5\"). It\'s small, clear, and unobtrusive, so it won\'t detract from the view of your aquarium.Simply place pH Alert® visibly anywhere in the aquarium or filter. It’s that easy. No chemicals or test procedures are required. When first put in service, response time will be about 30 minutes. Thereafter, pH shifts will register within ten minutes.