:smoking: Shaking isn't really needed unless they have been sitting for a long while, and even then it's not likely to have separated; those nutes are fully dissolved, no particulates typically,... that said, get to know their looks and smell and be super careful about cross contamination,... don't keep them anyplace warm or really cold,... cold can cause some things to precipitate out...
Lots of choices for pH meters on Amazon! I have a very basic HM pH80 that several years old now, and still works fine... but that's with good care... some come with replaceable electrodes so you don't have to buy the whole unit again if they go bad,.. this model isn't one, so far so good! ..looking, I see one for about $36.... BlueLab is choice too!
I'd check your calibration weekly at least in hydro,....
>> New pics:
--purpling on the stem is probably normal color expression.. just so you know, for diagnostics, pics need to be in normal light, grow lightsdistort true color too much, and that's often a key clue....
-- unless there's a real need, don't remove leaves.. theya re still functioning as power plants and reserves, even affected ones; removal doesn't fix things,... except aethetics!
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gahhh! growers choice again! I'm seeing several problem plants with their genetics,....most not auto'ing in a timely manner, or at all,... plain bad breeding!
....well, the nutes have Ca and Mg in them, but sometimes not enough; LED seems to put extra demand on them, and still, it's a strain-to-strain thing, even pheno's.... but other hiccups are likely triggers/causes.... you're all over those now though!