Apex Conductivity probe question

[BlackTip]

I calibrated the Conductivity/Salinity probe last night. I followed all of the instructions. I have the temp probe connected to the PM2 with COF of 2.2 as instructed in BRS video. It was calibrated in the tank water next to the Temp probe. Temperature was around 79F. I let it be in the tank overnight.

I measured the salinity this morning using Milwaukee Digital refractometer. I calibrated first using the included distilled water. The water temp from the tank was around 79F. The reading was 32ppt. The probe is reading between 31.4 - 31.6.

Is the difference acceptable? Do I need to re-calibrate the probe?

I sill have the calibration solution bag. The bag was left opened from last night. Is the solution still usable, or is it one time use?

Thanks,

 

[slief]

It takes time for the conductivity probes to break in. I would let it settle for at least a week and then recalibrate it. Make sure you have the temp probe in the calibration solution or make sure the calibration solution is the same temp as the tank water. I usually just place the temp probe in the cal solution. Also, when you calibrate the probe, make sure you give it enough time for the numbers to completely settle.

 

[BlackTip]

It takes time for the conductivity probes to break in. I would let it settle for at least a week and then recalibrate it. Make sure you have the temp probe in the calibration solution or make sure the calibration solution is the same temp as the tank water. I usually just place the temp probe in the cal solution. Also, when you calibrate the probe, make sure you give it enough time for the numbers to completely settle.

Can I re-use the calibration solution a week from now?

 

[slief]

Can I re-use the calibration solution a week from now?

I wouldn't. If there is any evaporation, the conductivity of the solution will have changed. I also use the Apex cal solution in the foil packs. I've seen variations with 53000 ms cal solution that comes in the bottles.