I'm not sure if I'm answering your question direct or not but I just read its important that all your chemicals and must sample are all the same temperature, preferably room temperature or you'll get false readings. This includes having chemicals at room temperature when calibrating your ph meter. I found this interesting because when I was at winery this fall in the lab the owner was getting ready to do some testing and he had everything sitting out on the counter to get acclimated to the room temp.