GroStar Pen Tester Tutorial Video
Lab-grade instruments designed specifically for growers.
00:30 How to calibrate pH (for GS1, GS2 & GS4)
02:38 How to calibrate EC (for GS3 & GS4)
03:50 How to test solutions
04:38 Pure water pH test
05:26 How to direct-test soil pH (GS2 only)
07:02 How to clean your probe
07:50 How to store your probe
08:35 How to replace your probe