You are making a lot of sense OneOnion. It seems to work best when people clearly label what each reading is, like giving
Ammonia - 3.5 ppm
Nitrite - 2 ppm
Decide what order you want to use and always use the same order so that we can just look down a column for the second number in each group, if that is the thing that you have a question about. Do not use dates, instead use Day 1 , Day 2 etc. That way we don't need to keep calculating what day you are on before examining the numbers. Once you start testing twice a day, mark each set of readings as 12 hours or 24 hours so that we can tell. All of this just makes it easier for those of us trying to answer questions to figure out how your cycle is going. For you there is only one cy6cle at a time, for me there are often 15 or 20 that I am watching and I get confused easily.