Conductivity Probe ????

[TandN]

Ok well I dont know whats goin on here lol. My Husband did a 10g waterchange while we tested the water. He noticed the profulix was showing a salinity of 1.029. So he calibrated our new refractormeter w/ pinpoints solution. He then tested the tank water. It read 1.024. So now theres a big diffrence. So he then tested the refractormeter w/ profulix's fluid and it was way off again. So he calibrated it according to the profulix fluid and tested the tank water it read 1.031. At this point I recalibrated the probe w/ the profulix fluid while he finished up the tests on the tank. When it was all said and done I sdipped the probe in RO/DI water to clean the fluid off it and put it back in place. And now its reading the tanks salinity is 1.021 !!!!!!!!!!!!!!!!! What the flip is going on ? Any suggestions ?

TIA

 

[AQD_ottawa]

Your not giving the probe enough time to settle most likely. other than that -

Make sure probe and solution are exactly the same temperature when calibrating.

Only use genuine GHL 50Ms solution to calibrate the probe.

I would also make sure the probe is very clean as you have had the unit for a while without use and the probe could be contaminated.

Tooth brush and vinegar

 

[TandN]

Yeah we used the genuine solution. The probe was spotless before I calibrated it the first time. It is in a dark area where theres no light and I cleaned it before calibrating it this time also just not w/ vinegar because its crystal clear. Its been about 30 inutes since I calibrated it and it still reads the same 1.021. I dont know what to believe at this point pinpoint w/ refractormeter profulix w/ refractormeter or the probe w/ profulix

 

[TandN]

So any words of wisdom ?

 

[Matthias Gross]

if you believe more pinpoint then you enter an "offset" for the salinity to correct the reading
->read manual, check ProfiLuxControl

 

[TandN]

Matthias thats what i am askin which one should I believe. This is your baby and if you think it is the best one then ill take that trust. Also should I re do the calibration and see or just off set it or hell the salinity is really 1.021

 

[AQD_ottawa]

simple answer

GHL probe platimum plated used in the chmeistry industry and supplied with accredited certificate of accuracy.

I think my money would be on the GHL probe, providing it is kept clean and I mean cleaned correctly.

 

[TandN]

lol Yes Mike I know Im just gonna colibrate it again and see what it says and believe it

 

[AQD_ottawa]

Clean it well first!

the reason i say this is because I know for a fact your probe has been idle for at least 8 months and probably longer since manufacture and will have micro tarnish on it that will need removing.

Can of full fat coke over night! or better vinegar then clean with mild detergent and rinse very well otherwise your fish will be for ever blowing bubbles........

 

[TandN]

ok pure vinegar or water w/ vinegar ? what type of mild detergent ?

 

[AQD_ottawa]

Pure vinegar - malt - distilled - garlic flavoured- makes no odds - Vinegar

ANY mild detergant

 

[TandN]

FWIW I calibrated it then cleaned it and put it back into the Profilux fluid and it read 1.0227 / 49.7mS

 

[AQD_ottawa]

try cleaning it then calibrating it and as I said above.

Please follow my direction

 

[TandN]

Mike and Matthias ???????

Ok I did as told to do about cleaning. Now I decided for the heel of it to put the probe into the solution and see what its reading now. Its saing 51mS/1.0238. I went to pinpoints page on what 51mS should be and it was 1.0248. Why is it diffrent ?

http://www.americanmarineusa.com/salinityconversion.html

 

[AQD_ottawa]

matthias has the answer to this, but as explained on the forum before there are more than one ms/ gravity conversions

matthias will explain the finer details

 

[TandN]

Yes please I just wanna understand why its diffrent. And that is gonna be the reason why I was getting all these diffrent readins when I was calibrating it.

 

[kidney514]

Just read in the native mode, there is no conversion and it's open to any interpration.
Just read in mS.

 

[Matthias Gross]

yes, that's right: the only reliable (correct) value is conductivity (mS) - if the temperature compensation during calibration and normal operation is OK!
all other values are converted (calculated)

 

[kidney514]

<a href=showthread.php?s=&postid=13903275#post13903275 target=_blank>Originally posted</a> by kidney514
Just read in the native mode, there is no conversion and it's open to any interpration.
Just read in mS.

Meant "it's not open to any interpration"