This is my understanding of it, so if I have misspoke please call me out.
That's pretty much it in a nutshell. I ran the 20-10-20 fert for about a week and a half to get the pH back down into the correct range (under 6.2pH). My ProMix HP was about 14 months past the manufacture date, so 2 months past the best-use-by date under
ideal of storage conditions. These were stored in the sun in the heat of Burbank CA, so knock a few months off from that and you can see where the problems started.
On the topic of MegaCrop and folks seeing issues in flower and the possible lockouts folks see if they use too much, I have a thought that came to me while catching up on this thread, (ignoring the type of N they use and its effect on pH - which the folks at GLN don't believe to be true). I'm not committed to this (and it may not be all that original), but thought I would put it here for discussion:
When most of us went with MC, it was because it was a simple and inexpensive way to fertilize our plants. One product, weigh it, mix it, feed. Easy. Then came the discussion about whether
their NPK ratio was the
correct ratio for cannabis after being told that plants need much more P in flower than they actually do. And it turned out that plants don't need to be hit with high levels of P to produce big buds.
And then came the lockouts that many folks found if they got a little too high in the feeding.
What we haven't discussed is the fact that GLN may have gotten the ratios wrong, or at least not ideal for your specific plant. Maybe their 9-6-17 and their amount of Ca and Mg aren't balanced to what your individual plants need. And there is no way, using a single product, to dial up (for example) the N without pushing one of the other elements into the lockout zone.
