Sorry Mp, my phone is off it's axis. Just saw your question.
You wait until pH stops changing. I know that isn't very helpful, but adding more of acid or base until you have a stable reading will cause you to overshoot which is what I think happened to peg your meter.
I used a cool most many, many, ah hell too long ago to count, on cakes. I didn't want anything adding heat to my makeshift prehistoric Martha residing in the SW desrt. Imagine 1/2 A frame built from styrofoam insulation board with sheet plastic covering the open front. Those were the days.
See I asked about this before about coir thinking it was structure and was told coir is slow nutes. I would say let's get our ducks in a row, but would hate us all chasing the wrong tangent. Perhaps some collaborative testing? Just not sure how to go about it. Any ideas?
No. My understanding is they simply provide some form of nutrient to help pull the mycelium growth through the coir substrate. Fruiting is a response to starvation and evaporation from what I understand so the less nutrients the shorter the time to fruit.
How much time should you wait after adding lime to take a new Ph reading? I would assume adding untreated coir to high Ph coir would bring down the Ph level to an acceptable level. If I am wrong in this assumption let me know. If I should toss it let me know that as well.