so im sure the ph meter is off. im waiting to get ph4 in the mail but i went to pharmacy and got distilled water which should be ph7 right? well my hanna goes initially to 7.8 then drops to 6.5 and if i move it or stir the numbers jump all over the place. i have ph paper strips but they do not change color at all and that color represents a ph of 5- 5.5. whats going on here?