Afroman25 Well-Known Member Nov 4, 2008 #1 I have a digital PH pen that i haven't used since my last grow January 07. I am starting a new grow soon. Will i need to calibrate it or should it be fine to use?
I have a digital PH pen that i haven't used since my last grow January 07. I am starting a new grow soon. Will i need to calibrate it or should it be fine to use?
