Wait nvm I just looked when I posted the first time i was sure I put a link there I had clear memory of doing it but I was the one who was stoned lol.

Luster Leaf Products, Inc.: RAPITEST SOIL pH METER [716750] - pH, EC & TDS Meters & Test Kits for Water & Soil, Timers, Instruments & Calibration Solutions - Horticulture Source