Jeff, sorry for the delay. I've not been looking.
I make a page in excel with Date, Time and e.g. Temp, or pH or Redox and I have three separate graphs. I just started to keep a running log on Excel.
If you do them together, it is difficult because the scales are so different. If you have 8-8.4 on one axis, on the same axis you must have 350-400, or even 78-80 and it just doesn't look good or is difficult to read.
Try making a page (sheet) for each, with DATE, TIME, Measurement. and then graph it.
I just copy the text file that Profilux makes and past it into the Excel worksheet at the bottom of the last entry. This gives me a running total. Then I past the individual data onto its particular page.