I think that is normal,mine always goes up a little everyday,another reason to change nuits weekly

I don't know anyone who uses Ph up,if you have already used ph down, all your doing is making salt they won't,can't use.better to drain and refill with new nuits

always rinse real good before returning prob to storage
Daddynobucks Reviewed by Daddynobucks on . Ph meter Does the tip need to sit in the buffer solution or distilled water? Rating: 5