Measure with confidence. HI9814 GroLine Waterproof Combo Meter for pH, EC, TDS (ppm) - HI9814 SRP $259.00 No time to waste. Start testing faster with Quick Cal mode to perform a single point pH and EC/TDS calibration with one solution. Higher quality measurements. With high resolution and high accuracy, your results are more accurate than ever. Test anywhere, anytime. Our GroLine Portable Meter is waterproof to withstand your grow environments.