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?

http://img.tapatalk.com/d/12/11/18/ata2u3yr.jpg

http://img.tapatalk.com/d/12/11/18/zade4ehu.jpg
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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.

[benner]

You are definitely doing all you can to reduce the risk of failures.....good for you for understanding the failure can and will occur....a lot of people want the buy it and forget or the double click of a mouse solution.....this is just not possible with reef tanks....I do not know anyone in the reefing hobby who has never had a failure, a minor crash, a major crash, or worst of all a complete system crash....you will soon find out who is dedicated to the hobby and who is not lol


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[benner]

Here is a question that has been bothering me for quite awhile.....
Why does ghl produce 50ms calibration solution and not 53ms? Are some people keeping reef tanks at 50ms? I do not know of any other companies doing this and I do not understand how it is beneficial.....a 53ms solution would help me more because then I could put the probe into it and see if it reads what I keep my tank at which is 53ms or very close to it. For this reason, I do not use the ghl solution..... I prefer using 53ms like every other person I know in North America....


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[Gunther]

Why does ghl produce 50ms calibration solution and not 53ms?

The solution is - as the name suggests - made to calibrate probes. It´s nice to have it near the value you want to measure at the end, but that´s not mandatory. Even if it´s lower ot higher, it will be good what it´s made for.

In europe (where GHL products are comming from) the 50ms solution is standard from most suppliers - but for the target this doesn´t matter. Both is o.k. for calibration purposes if you use the corespondendig values and ensure that the solution has the right temperature

Maybe reason is the same why you guys still use such crude units like inch, foot and mile ... :p

[Matthias]

problem solved thread closed