Strange readings from conductivity probe!

[benner]

Check out these readings from my conductivity probe as seen on my profilux touch.....this has been happening now for the last couple days.....salinity level slowly drops down low and then all of a sudden will be back at normal....my norm is 53ms and you can see in the first pic that it is almost at 52ms...yesterday it was at 51.8.... There is no water being added to the tank and refractometer shows no change so it has to be the probe.....has anyone experienced this before?? Is it just a matter of recalibrate the probe?




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[doggydoc10]

Yeah benner. I went thru that before. Calibrated the probe. Problem solved.
Try leaving the cal solution in the sump for 24 hours then put the probe in the cal sol and see what it reads. I figure mine needed calibration that way. It was off 1.25. I re calibrated. Dead on!!!

[benner]

Ok thank you! I am glad to see others have had this issue.....I will put the solution in the sump now for later tomorrow!


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[benner]

I have solved my issue without having to recalibrate the probe.......I did this a week ago and decided to post my doings and results
I took the probe out and rinsed it well in rodi water and when I reinserted the probe into the holder it read correctly again and has remained stable ever since.....
I am going to see how long this will hold out before having to recalibrate probe....
Have you ever tried this doggydoc?


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[doggydoc10]

I did rinse and clean it but I also re calibrated it so not sure if rinsing alone would have done the trick!!!!
Hopefully that will work for you.
Please keep us posted.
Good luck.

[benner]

I will! Sorry I was tardy....


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[JasonK]

How often would a cond. probe need to be replaced?


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[Antipodes]

How often would a cond. probe need to be replaced?


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Very Rarely!
Two platinum electrodes which you would have to sand or be eroded with a caustic solution, they could be broken. To all intensive purposes, they will last a lifetime and certainly the lifetime of the computer itself.

"Platinum is an ideal material for not only jewelry, but also in electronics and chemistry because it does not oxidize, is tarnish- and wear-resistant and has high resistance to erosion from other chemicals."

Like the posts above have shown, they require reasonable constant housekeeping, as small amounts of algae, film will cover the surface of the electrode and will provide a small resistance to the already very low current flow required to measure the electrical resistance of the water.

As a note, I recalibrate my probes every six weeks and check the reading of the conductivity probe every week with a known sample. I do this as I am using the conductivity to alter the top up if it is high or low with RO or sea water.

[benner]

Very Rarely!
Two platinum electrodes which you would have to sand or be eroded with a caustic solution, they could be broken. To all intensive purposes, they will last a lifetime and certainly the lifetime of the computer itself.

"Platinum is an ideal material for not only jewelry, but also in electronics and chemistry because it does not oxidize, is tarnish- and wear-resistant and has high resistance to erosion from other chemicals."

Like the posts above have shown, they require reasonable constant housekeeping, as small amounts of algae, film will cover the surface of the electrode and will provide a small resistance to the already very low current flow required to measure the electrical resistance of the water.

As a note, I recalibrate my probes every six weeks and check the reading of the conductivity probe every week with a known sample. I do this as I am using the conductivity to alter the top up if it is high or low with RO or sea water.

I could never trust the profilux enough to allow this kind of actions on my tank.....
I have found the probe to be unreliable.....if it needs this much attention then it ill never control anything for me....it will monitor only.....too much risk IMO.


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[Antipodes]

I could never trust the profilux enough to allow this kind of actions on my tank.....
I have found the probe to be unreliable.....if it needs this much attention then it ill never control anything for me....it will monitor only.....too much risk IMO.

Of course by all means. Each to their own systems. One of the reasons I like this controller as it is able to be configured differently by all sorts of users with different needs!

For me I find that I am significantly more unreliable than the controller as I don't seem to be able to look at the figures everyday, I certainly would not rely on me to control my temp, redox, ph and conductivity. I just can't seem to find the time. At least the way I do it I am ultimately assured that the figures the system displays is accurate and I have alarms set up for most over and under readings and to achieve this I feel my checking allows that sort of control.
However I am from the aircraft industry, and I am a pedantic sort of fellow who has taken his training home with him! Check, check and then recheck again.