The Alert Comboâ„¢ pack combines Ammonia AlertÂ® (1 card) and pH AlertÂ® (1 card). Ammonia AlertÂ® and pH AlertÂ® are almost half the size of competing products. At 1.5" x 2.5", they are small, clear, and unobtrusive, so they won't detract from the view of your aquarium. Simply place Ammonia AlertÂ® and pH AlertÂ® visibly anywhere in the aquarium or filter. Itâ€™s that easy. No chemicals or test procedures are required.