pH Alert™ Seachem sensor technology Continuously monitors pH in freshwater No tests, no strips Lasts up to 4 times as long as competing products DescriptionpH 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.DirectionsSimply 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.CareNo care is required beyond removing algae with a clean, soft material. Avoid touching the sensor with fingers, since skin oils can damage it. Do not use bleach, soap, detergents or hard objects to clean the sensor. Some dye medications may discolor the sensor. For maximum sensitivity, the unit should be read under natural daylight or daylight simulating light.