Continuous monitoring for both ammonia and pH in freshwater * Ammonia Alert provides continuous monitoring of free ammonia levels in the freshwater and marine aquaria and lasts up to 1 year * pH alert provides continuous monitoring of pH in the freshwater aquarium lasting up to 6 months * Small and unobtrusive in the aquarium; simply place alerts visibly in the aquarium or filter for monitoring * Package contains 1 pH Alert and 1 Ammonia Alert