Dude, I'm fucking pissed. This PH meter has to be off. I get home with 14 gallons of RO, and one tank I add a good amount of PH down cause Im working with 7 gallon containers. And it reads 5.9 and I am like fuck, I put too much, let me check the container with out any PH down. It read 6.4 so I was like perfect. I dump about a half a gallon on my worse plant, and check the run off and it reads 8.4.
Then I continue to flush another gallon and it read 9.1. WTF? So I stopped everything, and will wait till I test the meter in the AM. Keep ya posted.......