How do I know if my TDS pen is properly calibrated?

[_Dude]

I have a Hanna 98311 TDS pen set to .7 conversion factor. A few weeks back I ordered HI 70442 TDS Calibration Solution. I calibrated the pen in the solution and then checked the solution in measurement mode and it showed 1500ppm. Perfect, right?

Then I noticed in the manual that you need a specific kind of calibration solution from Hanna, HI7031, to calibrate the 98311. So I ordered HI7031 and just now I calibrated the pen with it. Except, it doesn't calibrate. Or if it does, I don't know how TF I'm supposed to verify. The manual says you just enter calibration mode, drop it into the solution, and it calibrates automatically. It's supposed to flash OK or something like that, then it's supposed to return to measurement mode. But it doesn't. It just sits in the solution reading "1500" and "USE" and with the "cal" indicator blinking until it automatically shuts off to save power (batteries are fine, reading 100%). When I turn it back on it goes into measurement mode and gives me a reading in the 800s for the HI7031 solution, and a reading in the 1200s for the HI70442 solution. This tells me the pen is all out of whack and not calibrated properly, but I don't know what I'm supposed to do to verify calibration because the manual doesn't say anything on the subject.

Like I said, the weird thing is how I got readings of 1500 ppm after I calibrated it with the WRONG solution (HI70442) a few weeks ago, and I don't think it's a coincidence that HI70442 says 1500ppm on the bottle. Should I just calibrate with HI70442 and move on?

I really don't have time for this shit and I'm about to order a new pen but I figured I'd see if anyone has any advice first.

Update: yeah, this is really weird. I just calibrated it with HI70442 and it sat there a few seconds and bam, went right back to measurement mode. And it's reading the solution at 1500 on the nose in measurement mode. Do I have to reset the pen or something? It's almost like it's decided it likes HI70442 and doesn't want HI7031 any more, lol.

 

[Moppel]

personally i dont think there is so much difference between the diff calibration solutions.

Dont you know the ppm from your tapwater, so you can measure that, to be sure its ok?

 

[avant gardener]

you can use 1500ppm solution as a known quantity to find out whether your pen needs calibration, but you CAN'T calibrate it with that. hanna pens only calibrate to 1413µs, or the other solution you have (HI 70031).

put your pen in ec mode. that's the one that says µs rather than ppm.
now hold the left button til it says "cal."
the display will say "use 1413"
do it.
when the pen is done doing its thing, it will say "ok."
ok. you're done.

here's a video of some broad doing exactly what i just said:
http://www.youtube.com/watch?v=gW5WgiQfa1g

personally, i think that hanna has gone downhill sharply in the last couple years, both on quality and customer service. i had one of their pH/tds pens and the thing lasted for a good 3 years of everyday use without a hitch. when it finally took a crap on me, i ran through 3 more in the next year before i finally gave up on them. apparently i'm not the only one who's had this issue either.

here's what else. it used to be that you could take them back where you bought them and they'd change out the probe or the brain, no questions, because hanna backed up their product. now they want a receipt and you've got to send it back yourself at your own expense and maybe they'll fix it and send it back in 3 or 4 months. funny that the new return policy just happens to coincide with their product going to shit.

i switched to bluelab. 5 year warranty. very pleased.