Not to confuse things even more but here goes:
In hydroponics, pH is important, notably that plants like it a bit more acidic than soil/growth media growing, but I would say that solution temperature is even more critical than pH. When growing DWC, which seems to be one of the most sensitive methods when it comes to pH and temperature, I could maintain excellent results from pH 4.8 - 6.4 from looking at my notes. However, performance increased notably when the water temperature dropped incrementally down to 64 degrees F (!!!!!). I could get it colder than that and eventually settled on an avg. daytime temp of 68 F.
When you think about it, it makes sense: colder liquids hold more dissolved oxygen. So the cooler the solution, the most oxygen is available to the roots. By feeling the mid-60 degree F water with your finger tips, it really feels cold, especially with air temperatures in the high 80's. But it really worked time after time, outperforming a control tank kept at 73 F.
Apologies if I hijacked/tangented this thread.