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slief
04/14/2013, 06:40 PM
I have an Apex with a conductivity probe. The probe has been in the tank for a couple years now. I have not calibrated in a year or so. Today was set to be that day. I pulled the probe from the tank and soaked it in vinegar for about 10 minutes followed by a good rinse in fresh tap water. I then followed the directions, dried and calibrated it. I used some 53000 solution I had laying around in those sealed foil bags. The bag were dated with a 4/21/2012 expiration date but I figured it couldn't be that far off.

None the less, I calibrated and after calibration I am seeing a 27.9 Salinity reading which equates to roughly 1.0205 specific gravity. I know that can't be right because I double checked my tank using a refractometer calibrated with 30ppt solution and the tanks reads 1.024 which also matches my hyrdrometer. I verifed the numbers in both Salinity Mode as well as high mode in the Apex condx settings which all result in a 1.020'ish reading.

So now my question is, would the expired 53000 calibration solution be that far off for calibration or am I likely looking at a bad probe? I compared both "high"

bvoss
04/17/2013, 05:52 PM
I have never had much luck with the calibration solution. I gave up and just stuck the probe in the sump and then manually adjusted the compensation parameter on the probe web page until the conductivity displayed matched the results of my calibrated refractometer.

Once it is calibrated, it stays very stable for months.

slief
04/17/2013, 07:10 PM
I have never had much luck with the calibration solution. I gave up and just stuck the probe in the sump and then manually adjusted the compensation parameter on the probe web page until the conductivity displayed matched the results of my calibrated refractometer.

Once it is calibrated, it stays very stable for months.

Hmmm... That is very interesting. I did get my probe calibrated once I got new solution and it does match my refractometer and my hydrometer but I certainly like that approach.

It would be nice if you could do that with PH..