To turn off the H2OPal tracker simply separate the tracker from the bottle attachment at the magnetic connection and place the original drop-shaped paper insert (or a similarly stiff but not too thick piece of paper or card stock) all the way between the battery and the top contact. This will turn off the H2OPal tracker. To reset the H2OPal please make sure the tracker has been turned off for 5 seconds or longer and then simply turn it back on again by removing the paper protecting the battery.
Please make sure the battery doesn't tear the separation paper between it and the contact as you are taking it out. If a small piece of paper remains between the battery and the contact, then it may not be able to get power from the battery and won't be able to turn on.