I see this every time I take the fam on vacation. It’s quite incredible really how drastic the swing is. For context, 2 adults, 2 kids, 2 dogs, aquarium in the basement.
Agreed. The best thing I ever did for my tank was to move it to a separate room, with a closed door.
Also, before I go on vacation I always increase my Triton dosing. Because I know that increased pH will lead to increased consumption of elements in the water.
Unless I'm reading your pH graph incorrectly, isn't your pH trending down? This is the opposite of what happens when we are out of the house, when it normally increases because fewer things are expelling CO2. Then Randy's observation is true, parties makes the pH plummet as well...