my sm101 is here and i have a question regarding operation that wasn't addressed in the manual. i understand that it is not advisable to let the probe dry out. so i assume that it is common practise to leave the probe in the tank continuously. the monitor is then turned on when the user wishes to find out what the pH is, then the unit is turned back off again until the next use. is this correct? i know this sounds like a boneheaded question but i want to get this right. thanks a lot in advance.