I was testing this morning how much my chlorine dropped over night and got two completely different results back to back. I was at 10Fc before i went to bed and when I tested at sun up I was at seven. My first reaction was Im going to have to shock for sure. I decided to check it again because I wasnt sure If i had put enough dpd in it. the next time I got a 9. Does the ammount of dpd make a difference in the outcome. bothe were full scoops, but the last one was over a full scoop.