Seachem Alert Combo pH and Ammonia

Ammonia Alert detects and continuously monitors free ammonia in marine or freshwater aquaria. The sensor, located in the center of the reference scale, changes reversibly from yellow to green to blue relative to the ammonia concentration.
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 to shifts in pH levels between 5.8 and 8.2. Freshwater Only.