I found this online, and it contains a wealth of pH and ORP info including temperature corrections, equations, etc.. Most is way beyond me, but I liked the the use of red cabbage or mushrooms to measure pH. Title is 'Back to the pHuture'. Yokugawa mfrs industrial instrumentation.
The link is: https://www.yokogawa.com/eu/an/analy...H_Handbook.pdf
The PDF file size is 5.3 Mb.