[Jay Tea]

Hey folks, I just acquired a Hannah Combo PH/DC meter model 98129. The pen was "barely used", when I got it. I bought the GH ph4.01 and 7.0 solutions and am getting some consistent but slightly inaccurate reading (1point). Anyone have any suggestions? Thank you.

 

[rubthe nub]

1.0 OR 0.1
There is a huge difference between those
calibration solution can vary because of temps
perhaps you're right at a temp variance
just my $.02

 

[MGRox]

Since you mention that it is "used"; you may want to let the probe soak in distilled, storage solution or 7.0 calibration solution for 24 hours and THEN calibrate it. If at any point the bulb tip gets dry for any length of time; it can throw off the calibration a pretty good bit.
Technically, if you pin down the Mfg's of those Pen's; they will say to calibrate them every time you use them. As opposed to a "monitor" style probe that is intended to be continually submerged in a solution; which should be calibrated monthly then.

Fwiw, I keep all my pens in a solution (not just in the cap) when not in use now as it holds calibration much longer (also multiple pens will give similar readings more often).
another $.02 to throw down into the kitty.

 

[Jay Tea]

awesome. thanks Nub and Ox, actually i have the probe submerged in a 70* degree solution right now, and im going to Radioshack manana for some new batteries. ill give my $.02 tomorrow!

 

[CelticEBE]

awesome. thanks Nub and Ox, actually i have the probe submerged in a 70* degree solution right now, and im going to Radioshack manana for some new batteries. ill give my $.02 tomorrow!

I noticed my hanna does better when I use hanna storage solution, versus the blue lab storage solution.

 

[G gnome]

Ive never been confident w those hanna instruments man. I went thru so many of those before i got a blue lab