Prepping/Cleaning Salinity Probe for Recalibration?

Kengar

Active member
I'd like to recalibrate my salinity probe.

When I got the Apex unit and was calibrating the first time, I wiped things off with paper towel because I couldn't get it to get in proper range for the dry part of the calibration (i.e., before putting in the solution). I don't recall whether the probe was covered with a cap and solution, but I think it was which is why I couldn't get the process to proceed initially; the paper towel, however, left lint on the sensor, so I'd like to rerun the calibration. (This is particularly because re-calibrated refractometer shows on the order of 31 or 32 ppt whereas the Apex is trending at 35-36......).

So, to prepare for recalibration, should I just swirl the probe around in some clean RO water then shake off and allow to air dry?

Thanks
 

slief

RC Sponsor
Premium Member
I'd like to recalibrate my salinity probe.

When I got the Apex unit and was calibrating the first time, I wiped things off with paper towel because I couldn't get it to get in proper range for the dry part of the calibration (i.e., before putting in the solution). I don't recall whether the probe was covered with a cap and solution, but I think it was which is why I couldn't get the process to proceed initially; the paper towel, however, left lint on the sensor, so I'd like to rerun the calibration. (This is particularly because re-calibrated refractometer shows on the order of 31 or 32 ppt whereas the Apex is trending at 35-36......).

So, to prepare for recalibration, should I just swirl the probe around in some clean RO water then shake off and allow to air dry?

Thanks

I’d put it in some distilled white vinegar for a few minutes to clean it. Then rinse it off and put it back in the tank water to settle back in for a day. Then calirbate as normal. I wouldn’t leave the probe out to dry. During the drying step, just shake the probe off well. There is no “proper” range during any of the settling steps including the dry part. Once you shake the probe off and let it settle until the numbers don’t change, proceed to the next calibration step then submerse it in the 53000ms solution per the calibration instructions. That’s the way I always recalibrate old probes and with new ones, I will place them in the tank water for a week or so before calibrating in an effort to break them in. I also allow the calibration solution to float in the sump for several minutes before calibrating to insure it’s the same temp as the sump water where my temp probes are located.
 

Kengar

Active member
There is no “proper” range during any of the settling steps including the dry part.

Hi Scott,

Thanks for replying.

When I did the initial calibration, the walk-through "wizard" has an initial step where it says to dry the probe. Having just gotten it, and not having had it covered with a cap/solution (I think, but not sure; I have twin tween girls and I don't recall what I had for breakfast an hour ago.....), I didn't do anything. But the process just kept going and going and going, with the value settled but NOT in an acceptable range according to the wizard. Rather, it had -- and kept having after repeated attempts -- the red exclamation point in triangle, like this:

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That is when I thought to myself, hmmmmm, try wiping it off with paper towel because Neptune really DOES want me to make sure this thing is DRY, e.g., not subject even to atmospheric humidity! (That's when I blasted it with a Wagner heat gun, too........ just kidding!) Subsequently, the calibration process went through but, as noted, I had paper towel fibers left on the sensor probes (inside the plastic housing) and readings have been a little "off." That said, I just got a higher-end refractometer ( https://www.amazon.com/Vee-Gee-Scientific-STX-3-Refractometer/dp/B004WDW70M/ref=sr_1_1?keywords=vee+gee+stx-3&qid=1551887139&s=gateway&sr=8-1) and the reading with it comports better with what the salinity probe shows.

Given downward trend I'm seeing, however, even though water levels are rock-steady with Genesis STORM, I'd like to recalibrate. The probes are in a corner of the sump where there shouldn't be microbubbles, but who knows .....
 
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