Indoor How often to Calibrate PH Pen?

[Heavily Medicated]

Is there a certain time period or number of uses before you are supposed to recalibrate your PH pen? What causes them to go out of calibration?

 

[bad dragon bzzz]

don't think so.time,knocks,is it in storage solution if needed,low battery,very high and low ph.any number of things.i calibrate mine every 2 months.

 

[Trapper]

I try to clean the nute residue off mine and store it upright filled with calibration/conditioning solution overnight
once every month or so and calibrate at that point. Just to be on top of it. It has never been more than .1 off
at any time. I've just found that it fluctuates less once cleaned up...gets right to the number and stops.

 

[GodAmJT]

I suppose it depends on your meter, and like these guys have said, how you take care of it. I have an HM waterproof, and when I first got it, I calibrated it once a month, and found that towards the end of the month, if I just checked it without calibration, I was up anywhere from 0.04-0.18 on the top end, and didn't really check with the 4.01 solution, although I've been told that you should go between both solutions until both readings come out perfect.. I didn't do that, and feel that may have affected my grows a couple of times.. Now, I'm checking the meter at least twice a week, but calibrating once a week when I do res changes..


What I do know, is that some of the standalone, or the real-time meters tend to stay in calibration a bit better, but I can't speak for all of them.. Bluelab and the CWPs seem to do well from the reviews I've read..