When selecting a supplier, prioritize the internal mineral composition. A premium stick should contain 99% pure magnesium, tourmaline, and calcium carbonate to effectively raise pH levels and lower Oxidation-Reduction Potential (ORP). Ensure the outer casing is made of food-grade 304 stainless steel to prevent corrosion and heavy metal leaching. Always request a water quality test report showing the stick can achieve a pH level of 8.5 to 9.5 and an ORP of -100mV to -200mV within 15 minutes of immersion.