Selecting the proper pH sensor electrode is critical for accurate, stable, and long-lasting water quality measurement. Different electrode materials and designs fit specific solutions and pH ranges, directly affecting measurement performance and service life. Glass pH electrodes are the most widely used, supporting a full pH range of 0–14. They deliver high precision for clean water, tap water, wastewater, aquaculture, and general aqueous solutions, but are not suitable for hydrofluoric acid (HF) environments. Antimony electrodes excel in harsh conditions. They resist HF corrosion and perform well in viscous liquids, sludge, and high-pollution wastewater, making them ideal for industrial and chemical applications. For special scenarios, high-temperature electrodes withstand elevated temperatures for fermentation and sterilization processes. Pure water electrodes are optimized for low-conductivity water such as purified and deionized water, with stable response in pH 4–10. When choosing a pH sensor, first check for HF content, operating temperature, water cleanliness, and target pH range. With the right electrode, you achieve reliable online monitoring and consistent industrial measurement.