yeah im sure. mustve recalibrated it ten times when i started all this, its pretty good meter all in all tho. its a hanna hi 9813-5 i got it comped to me by friend at an industrial supply. oh and they arent adapting to 9+ ph, its raising the run off ph to about 6.6 - 6.8 maybe a little higher sometimes. dont know why just yet but adding high ph water is keeping the run off at normal levels. 2 of them may actually need the water bumped up alittle more as their run off is still in the very low 6s or high 5s. they all have the same ffof soil from the same bag. did my best to mix it well and flushed a couple times before i put the plants in.
its something with my water, filter it and adjust the ph and it behaves oddly one way, dont do anything it acts odd a different way. im not trying to figure it out anymore so much as just work with it. so far if i put high ph in i get moderate ph out and they seem happier. im working on rdwc rig so i have control over the ph etc directly.