a few feeding ago my pin started taking longer for my reading so i replaced battery and calibrated  but still taking a long time get final reading now bing the rocket scientist that i am i remember adding just the wright size medicine bottle 4 my PH  pin 2 stand n so i checked the gallon jug and the medicine bottle NOT the same so i checked again NOT the same again like i said b 4 if it can happen i will b there with an A+ .......

i have those days to.