+1 to not removing the old cartridges.

I would leave your old cartridges in situ until you know what's up with the new test results. Rinse them in used water if need be but replacing them is not a good idea at this time.

LH he has not removed them yet.

To add.......storing water in pails only gets rid of chlorine but it should be aerated to do so and for a couple of days. However, this does not get rid of chloramines.......another product used in city water as a sterilizer and used in many water municipals.
+1
My understanding is that Chloramine is used by many cities precisely because it does not gas off like Chlorine. As mentioned, Prime takes care of both :-D.