CJ, Ken,
Do you guys ever hear of acid shock to fish in some waters out east that have border line PH and low alkalinity when heavy snow melts?
I'm familiar with the term, but I've not really seen it here.
I check the pH of my somewhat-alkaline pond water several times per year. When I do, I check the pH a number of times during the day. My pH can change from about 6 to 9 during the daylight hours, with it peaking mid-day.
If it warms enough tomorrow and I can maybe get some reasonable water samples, I will check the pH during the daylight hours. Unfortunately, most of the pond liquid will be from inflow from the forest floor, which will probably not be an accurate representation.
