NEPTUNE CALIBRATION FLUID PH 7.0 CAL7

Calibration is the key to attaining accurate readings from your aquarium monitors and probes, and even the most accurate probes can lose their calibration over a few months. Neptune System's 7.0 pH calibration packet is quick and easy: simple remove the top, stick your probe in, and perform the calibration procedure. Packet contains enough for a single calibration.