Mr.Growit, community. Today I was in the room organizing. Then i thought I need to recalibration my ph meter. For you newbies your ph meter, yes it needs to be calibrated. Not saying your stupid or anything, but you just don't know, some people go huh... and for the rest of us, ask yourself, " when we're my ph meters calibrated last"... Just a reminder guys, don't kill the messenger. I usually try to get to mine after each grow. You all have a good evening. Keep'm happily growing.

Good advice. I have a PH pen and it came with the 3 packs of calibration powder which I used up. How to do I make more of the calibrated water for testing? Do I need to purchase more packs of the powder ever time or is there some do-it-yourself method?