The SISO pH Tester is a, likely aquarium-focused, water quality testing kit designed for quick and easy measurements, often including 5 bottles of 10ml testing solution and a colorimetric chart for visual analysis. It is used to monitor pH levels in water. Other \"SISO\" or similarly named digital 4-in-1 testers (measuring pH, TDS/EC, Temp) are available for broader, precise testing.
