That's a nice log.
I use a log that I created and have two extra columns one for time test was done and one for comments. If I add chemicals I write it down and how much quantity in the comments. This way I can see patterns and can have a reference. Also in the comments, I write down when I vacumn, clean the filter ( I have cartridge) brush, heavy loads and so on. The time is not that important but it is useful when I test in the mornings on some occasions.