Expertly Calibrate Your pH Meter for Maximum Accuracy Why Use pH Buffer 7 & pH Buffer 4? For the most precise and reliable pH readings, always calibrate first with pH Buffer 7, then pH Buffer 4. Provides accurate two-point calibration using trusted reference standards Ensures consistent, dependable measurements over time — even as the meter ages Confirms meter performance and helps identify/correct any drift or inaccuracies Essential for hydroponics, aquaponics, soil testing, lab work, and more Simple Two-Point Calibration Guide Follow these steps in order for best results: Pour enough pH Buffer 7 into a clean container to fully submerge the pH probe. Place the probe into the solution and calibrate the meter according to the manufacturer’s instructions. Remove the probe, rinse thoroughly with tap water, and discard the used pH Buffer 7 (do not reuse). Repeat the process using pH Buffer 4: pour fresh buffer, submerge the probe, calibrate again per manufacturer instructions, rinse with tap water, and discard the used buffer. Immediately store the probe in GT pH Probe Storage Solution (never in plain water). For optimal accuracy, recalibrate weekly or before each critical use. Storage Recommendations Store both buffers (and your pH meter when not in use) in a cool, dark place away from direct sunlight or heat. These high-quality, NIST-traceable buffers deliver the precision you need for consistent, trustworthy pH results every time.