If we leave out graphs, we can use one for all

If we don't consider the graphs at the moment, but just the values the thing produces, we could use one meter to hang for a few days in one system, a few days in the next and so on. I have a feeling this meter is very slow - why wouldn't it - because water changes are very slow as well. You have to soak it for 24 hours before using it, so I think it will give the right values only after 24 hours, so it would have to be in one system for a few days is my guess.