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Alvizon
07.03.2017, 13:45
http://forum.aquariumcomputer.com/showthread.php?12045-Conductivity-Probe-values-drifting-down

i read this topic and cross post also here...

GHL staff can you tell me if maybe also conductivity probe can suffer of interferences or miss calibration??

yesterday i re-calibrate again at show 34.5 (like a rifractometer perfect calibrated with FM-reference solution.

today nothing change in tank and sump and again 34.1 ... i bet that this evening i will read under 34 PSU.. why happen?

Vinny
07.03.2017, 16:08
The accuracy of any probe is dependent on the precision of the calibration. The Conductivity readings are tied to the readings of your temperature probe. As such, as your temperature fluctuates throughout the day, the conductivity probe is also subject to change slightly.

Comparing the readings to a refractometer is only useful when you know that the temperature of the test fluid is the exact same temp as the tank temp. Otherwise, there will be a difference in readings from both measuring instruments.

thatanos
07.03.2017, 19:22
I have the same issue, When I calibrate the probe, I used to introduce the plastic protector where I made the calibration into the sump for minimun 20 minutes in order to have the same temp at the temp probe than in the calibration solution. I have calibrate it like once per week, but it always show me a big different (from 1.016 to 1.021) and everytime I check whith a refractometre it is between 1.025 and 1.026, I have also tested the calibration fluid and it shows the correct amout so I donīt know exactly how to wrk with it, as the temp itīs not causing the fluctuacion.

any ideas?

JayHoe
07.03.2017, 20:59
I read somewhere about someone having similar issues and it was due to micro bubbles collecting underneath the probe. I hope this is the case as I will be reling on mine once installed!

doggydoc10
07.03.2017, 23:41
I read somewhere about someone having similar issues and it was due to micro bubbles collecting underneath the probe. I hope this is the case as I will be reling on mine once installed!



Correct.
I used to have the same issues with my P3 and once micro bubbles were taken care off the probe was more steady and without downward swings


Sent from my iPhone using Tapatalk

dawsokj1988
08.03.2017, 17:10
I believe my issue is microbubbles as well. How did you eliminate them? I'm going to move the probe to directly in front of the inflow to see if the high flow will alleviate the bubbles.

doggydoc10
08.03.2017, 17:21
Moving the probe to a lower flow area.
I also just purchased the cell GHL sells for probes. Waiting for my new build to install


Sent from my iPhone using Tapatalk

thatanos
08.03.2017, 18:00
I have mine on the sump, previously I have it near the protein skimmer out take flow (vertex 150, just water flow), now I changed it yesterday to the first part, where the aquarium download flow is located (just opposite of the sock, and itīs imposssible to have microbubbles in those 2 positions but it works with the same values cycle

any more idea or sugestions?

ReefClownMIA
09.03.2017, 18:37
I have mine on the sump, previously I have it near the protein skimmer out take flow (vertex 150, just water flow), now I changed it yesterday to the first part, where the aquarium download flow is located (just opposite of the sock, and itīs imposssible to have microbubbles in those 2 positions but it works with the same values cycle

any more idea or sugestions?

Both locations are highly prone to microbubbles. I'd have a look at locating them in either lower flow areas, or active flow setup, such as a manifold, or better yet, the Measurement Cell GHL offers.

Yosh01
09.03.2017, 21:28
Yes - I agree to the microbubble theory :-) But can anybody explain, why in my case the IKS conductivity sensor is reading correct values (mounted in the same holder 2cm away) - with microbubbles?
The IKS module is ten years old!!! And works correctly from the beginning.

I assume, that it has something to do with the way the probe is build.

The IKS probe is mounted in a PVC fitting and the sensor plate is realy big (2x1cm). Also the sensor plate is mounted in a 45degrees angle to the pvc fitting. Above there are air holes (now I am knowing why there are "holes" :-) ). The fitting has a diameter of 4cm. I have never understood why - until now... If I put the sensor horizontaly/ parallel to the overflow - I have the same behavior like the PL4 with the IKS.
The bad thing ist, that this module can not be used with the IKS (because itīs the first generation without BNC coupler and with integrated circuit box).
In this moment, I am printing an comparable housing/ holder for my sensor including a bubble trap with my 3d printer.
Hope that helps. I have no more options in the sump to prevent micro bubbles.

JamesD
09.03.2017, 22:13
i have a similar issue with the conductivity probe, jumping around by a significant amount. Yes, it may be the effects of micro bubbles, but if that is the case, why is my old P3 probe which is inches away not having the same issue, I got a replacement temperature probe because the old one was reading significantly higher than the P3 probe and a lab grade thermometer but i still have the same issue with the salinity probe. I've calibrated it a number of times now.(if you are wondering why i have both P3 and P4 in same tank it is because the P3 is connected to my old doser and Ive been waiting months now for a doser 2.1)

dawsokj1988
09.03.2017, 23:08
Print me one!

thatanos
10.03.2017, 16:59
9234

I have change the position and have upload it to the aquarium directly as you can see at the image, but after 3 hours it is still on the same values (1.0218)

more ideas?

JamesD
12.03.2017, 12:24
My old P3 conductivity, connected to my P3, stays constant but the new P4 probe readings fluctuate , but if I take the new P4 one out and put it back in the water it is ok. Therefore I think it is, as others have said, due to micro-bubbles . I wonder if new sensors tend to attract these more than old ones. Old and new probes were close together in my sump.
Ps don't shake the probe when you take it out as I just did, catching the corner of the sump and smashing the glass probe! A very expensive shake!!
I guess this gives me a chance to plug the old P3 probe into the new P4 and see if it fluctuates whilst I order a new conductivity probe.:(

huub1983
15.03.2017, 07:22
My probe is the Same. Everyday less reading. Take it out en put it in the water and it's oké

Verstuurd vanaf mijn SM-G900F met Tapatalk

dawsokj1988
19.03.2017, 16:44
Just refreshing this issue. It's still very real and apparent. Any solutions to this besides buying a $100 cell with hopes that it will solve it?9265

Tinpot
19.03.2017, 21:33
I'm not sure if this helps or not but I have the conductivity probe on a freshwater tank and I am not experiencing this issue.

decena
26.04.2017, 07:40
I have the same problem with P4. The probe read less every day. I don't have micro bubbles and I have calibrated it three times. It starts 1025 and two days later 1024 I need to recalibrate it. Any solution?

totorus
26.04.2017, 15:13
But is the salinity value on your profilux is correct?
To me from other values that do not correspond to density
Example refractometer 1.026 ---- probe 1.054

because ?

decena
26.04.2017, 15:32
Yes the value on my profilux is correct 1025. But it read less every day :

Sunday: 1025
Monday:1024.5
Tuesday: 1024
Wednesday: 1023.5

I Need to recalibrate it every two days.... no bubbles, no dirty.. do I need to remplace it? I received the P4 five days ago...
I hope GHL can solve it. It's a general problem

decena
26.04.2017, 15:45
Yes - I agree to the microbubble theory :-) But can anybody explain, why in my case the IKS conductivity sensor is reading correct values (mounted in the same holder 2cm away) - with microbubbles?
The IKS module is ten years old!!! And works correctly from the beginning.

I assume, that it has something to do with the way the probe is build.

The IKS probe is mounted in a PVC fitting and the sensor plate is realy big (2x1cm). Also the sensor plate is mounted in a 45degrees angle to the pvc fitting. Above there are air holes (now I am knowing why there are "holes" :-) ). The fitting has a diameter of 4cm. I have never understood why - until now... If I put the sensor horizontaly/ parallel to the overflow - I have the same behavior like the PL4 with the IKS.
The bad thing ist, that this module can not be used with the IKS (because itīs the first generation without BNC coupler and with integrated circuit box).
In this moment, I am printing an comparable housing/ holder for my sensor including a bubble trap with my 3d printer.
Hope that helps. I have no more options in the sump to prevent micro bubbles.
As i have ordered the PL4 my hope was, that I will benefit from the last 10 years of eveleopement, IKS has missed.
Seems that I was a way to optimistic.

Could you please show a photo?

dawsokj1988
27.04.2017, 02:56
I still haven't figured out the solution to this. I've tried moving the probe around to various locations, with no success. Does anyone currently run the P4 with the probe cell? Could you post your salinity measurements? Here's mine.9373 The spikes upward are when I pull the probe out of the water and put it back in.

decena
27.04.2017, 07:24
I still haven't figured out the solution to this. I've tried moving the probe around to various locations, with no success. Does anyone currently run the P4 with the probe cell? Could you post your salinity measurements? Here's mine.9373 The spikes upward are when I pull the probe out of the water and put it back in.

+1. I hope someone has run the probe cell and can help us.

Matthias
27.04.2017, 10:33
we had this topic, decreasing conductivity reading over some time, in the German part of this forum, too

we contacted these customers directly to find out what is going on, the results were:

- electronics and firmware of ProfiLux 4 is 100% OK
- changing the probe - EVEN FROM OTHER MANUFACTURERS! - didn't change the situation, after a few days the value fell again
- and now the most interesting part: only tipping the probe very slightly (without removing the probe out of the water!) recovered immediately the correct reading

-> we assume that there are micro bubbles which have disappeared when touching the probe

one customer dislocated the probe a bit and it seems his problems had gone

I think the sensor should be somewhere where more flow is, to remove potential air

PS: Reading this thread may give the impression we would have here a general P4 or even GHL problem. This is NOT true.
We have here some cases, but on the other hand we have meanwhile > 1000 P4 users WITHOUT problems.
AND: we are using these probes UNCHANGED for many years now, it is not correct to say these probes had a general problem

-> please try the probe somewhere else - I am not sure which tactic is better: a place with less flow and maybe less bubbles or more flow which removes the bubbles

Vinny
27.04.2017, 14:26
we had this topic, decreasing conductivity reading over some time, in the German part of this forum, too

we contacted these customers directly to find out what is going on, the results were:

- electronics and firmware of ProfiLux 4 is 100% OK
- changing the probe - EVEN FROM OTHER MANUFACTURERS! - didn't change the situation, after a few days the value fell again
- and now the most interesting part: only tipping the probe very slightly (without removing the probe out of the water!) recovered immediately the correct reading

-> we assume that there are micro bubbles which have disappeared when touching the probe

one customer dislocated the probe a bit and it seems his problems had gone

I think the sensor should be somewhere where more flow is, to remove potential air

PS: Reading this thread may give the impression we would have here a general P4 or even GHL problem. This is NOT true.
We have here some cases, but on the other hand we have meanwhile > 1000 P4 users WITHOUT problems.
AND: we are using these probes UNCHANGED for many years now, it is not correct to say these probes had a general problem

-> please try the probe somewhere else - I am not sure which tactic is better: a place with less flow and maybe less bubbles or more flow which removes the bubbles

We've also conducted a test on an established system and have found no drastic changes in Conductivity.
9386

totorus
28.04.2017, 15:32
Hi vinny
I also like the others I have problem .. I recalibrated probe and moved on the other side with strong flow ...
To me also to incorrect salinity values ...
Tonight rewind all new calibration and move again probe into another area. And wait 2-3 days to see if anything changes.

Vinny
28.04.2017, 16:29
Hi,

Since these probes are very sensitive to micro bubbles, it would be best to place it in an area where you do not see micro bubbles developing from the tank's drain setup or skimmer. Skimmers can also release some micro bubbles over time. Depending on the direction of the flow and probe placement, these bubbles can travel in the direction of the probe and get trapped before they reach the surface. Perhaps positioning them in an angle will help provide a more stabilized reading.

In our test setup, we have the probe positioned in the same compartment as the return pump, just tucked away in the corner. This area does not have any drain plumbing and is in an area that I would consider to have moderate flow. Enough that no air bubbles develop as water travels over the sump baffle walls.

dawsokj1988
28.04.2017, 16:54
- electronics and firmware of ProfiLux 4 is 100% OK
- changing the probe - EVEN FROM OTHER MANUFACTURERS! - didn't change the situation, after a few days the value fell again


This test only eliminated one of the variables, not both. Other sensor probes were hooked up to the PL4 with the same result, which implies it could indeed be the PL4 causing the issues, not the probes themselves.

I would still like to believe that microbubbles are causing this. I've tried several locations within my sump, including high flow areas and low flow areas, with no general improvement on the drift. I don't mind purchasing the cell to house the probes, I'm just trying to look for confirmation that this will indeed solve the issue.

Also, generally speaking, less than 10% of a consumer base actually participates in forums. A smaller number of that subsect actually posts (where a lot of people just read the forums looking for solutions). When multiple (over 5) people actually post about the issue, that most likely translates into a larger population encountering it.

I'd also like to mention that I'm overall very satisfied with the PL4 and the Doser 2.1. It's just these little issues I'm looking to solve.

Cheers!

Matthias
28.04.2017, 17:51
the electronic circuit of the conductivity probe port is identical to the P3 and the expansion cards (there was no need to change a perfectly working system), I have problems to understand why the P4 should behave then different

but we are aware that here is a problem for some users and believe me, we want to solve this as soon as possible

we have to consider all possible options, even a bad batch of probes (although the manufacturer already said he doesn't believe this)

-> I think here helps only direct personal support


To all customers with this conductivity-issue

please contact us directly and let us go from there:

USA: info@ghlusa.com

all other regions: info@ghl-kl.de

decena
29.04.2017, 10:47
Hi, I think I've solved the problem.. I'm not sure, but in the las 24 hour the probe is reading the same. It doesn't read less every hour as before. I haven't changed the position of my probes, it's on the same place. But I have installed a new flow pump (small) "Sicce Voyager Nano 1000 l/h".The pump is at a distance of 20 cm. And the most important detail (I hope I can explain this correctly, I don't know much English):

- The flow is in the same direction as the probe slot. I attach an image, but if you have any doubt please ask me. In the next two days I am going to watch it to confirm if I'm right.

9396

Matthias
29.04.2017, 14:16
yes, this is what I think

with the flow you get rid of the air between both platinum electrodes

I am discussing this at the moment with our probe manufacturer, I must ask you all for some more patience, I think this will take another 2-3 weeks until we have a reasonable solution

until then I recommend to bring the probe into flow, the slot must be in line with the flow

or tip the probe daily until we have the solution

sorry for the trouble, but we have to wait for the probe manufacturer

JayHoe
29.04.2017, 17:33
I just thought I would check mine...

My P4 was reading 1.0241 and using a red sea sea water refractometer I got a reading of 1.026, so a difference of 0.02.

I recalibrated the probe and it reads 1.0247.

The previous calibration was on 4/4/17, 24 days ago and it has wandered down by 0.006 which I don't think is bad. I am using it to control my salinity so if it reads low, I will be topping up with SW more often than required and raising the salinity. As it stands, a once a month recalibration is not a great chore.

totorus
29.04.2017, 22:25
yes, this is what I think

with the flow you get rid of the air between both platinum electrodes

I am discussing this at the moment with our probe manufacturer, I must ask you all for some more patience, I think this will take another 2-3 weeks until we have a reasonable solution

until then I recommend to bring the probe into flow, the slot must be in line with the flow

or tip the probe daily until we have the solution

sorry for the trouble, but we have to wait for the probe manufacturer

Ok
Waiting for your news

totorus
03.05.2017, 12:48
After so many tests and positions
I confirm that it is on bubbles
Just that also moving across the sump
The value is never correct
Shaking the probe back to normal speed
After returning to distorting values
I hope we find a solution

decena
04.05.2017, 10:22
I thought the problem had been solved. But since yesterday the probe read less every time. I didn't make any changes in the position of the probes. Very strange.. It had been working properly one week. Waiting for news, thanks.

totorus
05.05.2017, 21:13
Screen

totorus
16.05.2017, 21:32
News?????

JayHoe
17.05.2017, 11:12
I was noticing getting thru more SW top-off than normal. The probe was reading 1.0242. I wafted the probe back and forth in the water and it shot up to 1.0252. The salinity on my refractometer is 1.029!!! Yikes.

This will be an issue for me...

alekslyse
26.05.2017, 23:02
I can also confirm this. I moved the probes to the return chamber of my sump to prevent as many bubbles as possible, calibrated etc and putting the probe next to the temperature probe. The first 10-30 min it show correct 53ms then it start to drop as micro bubbles start to form. Now an hour later in at 52ms and still dropping. If I wiggle the probe, remove the bubbles etc it jumps back up to 53 and start dropping again. (It does not stop at 52 it start to drop faster and faster down to low 40s).

Matthias
27.05.2017, 08:33
maybe some oversaw it:

I asked everyone who faced this problem to contact us DIRECTLY:

please email to support@ghl-kl.de

as soon as we have the final answer which works for everyone we will post it here

Lasse
18.06.2017, 16:33
Hi, I think I've solved the problem.. I'm not sure, but in the las 24 hour the probe is reading the same. It doesn't read less every hour as before. I haven't changed the position of my probes, it's on the same place. But I have installed a new flow pump (small) "Sicce Voyager Nano 1000 l/h".The pump is at a distance of 20 cm. And the most important detail (I hope I can explain this correctly, I don't know much English):

- The flow is in the same direction as the probe slot. I attach an image, but if you have any doubt please ask me. In the next two days I am going to watch it to confirm if I'm right.

9396

I solved my problem in a similar way - I direct my main return flow from the display tank to hit the probe – it works great now for more than a month

Sincerely Lasse

JayHoe
22.06.2017, 19:54
I have done something different - I placed my probe so it sits in a 'upflow' section of my baffles so that water is constantly flowing vertically up into the bottom of the probe. Seems ok so far.

decena
06.07.2017, 10:32
Five months later.. we are still waiting... GHL, any official solution?

Matthias
07.07.2017, 07:17
Five months later.. we are still waiting... GHL, any official solution?

It has been solved for a while now. We asked every customer who had this problem to contact GHL DIRECTLY.

Please do this. If you already did you and we didn't reply I have to apologize, then your email maybe got lost. In this case contact us again, please.

JayHoe
08.07.2017, 19:01
I must have missed that. My soultion above just seems to slow the problem, so I've come back. What is the best email address to use please Matthias?

ReefClownMIA
09.07.2017, 18:01
I must have missed that. My soultion above just seems to slow the problem, so I've come back. What is the best email address to use please Matthias?

Hi Jay - have a look at this, was posted on one of the prior pages in this thread.


the electronic circuit of the conductivity probe port is identical to the P3 and the expansion cards (there was no need to change a perfectly working system), I have problems to understand why the P4 should behave then different

but we are aware that here is a problem for some users and believe me, we want to solve this as soon as possible

we have to consider all possible options, even a bad batch of probes (although the manufacturer already said he doesn't believe this)

-> I think here helps only direct personal support


To all customers with this conductivity-issue

please contact us directly and let us go from there:

USA: info@ghlusa.com

all other regions: info@ghl-kl.de

JayHoe
09.07.2017, 18:56
Many Thanks Marco!

decena
11.07.2017, 17:00
It has been solved for a while now. We asked every customer who had this problem to contact GHL DIRECTLY.

Please do this. If you already did you and we didn't reply I have to apologize, then your email maybe got lost. In this case contact us again, please.

Thanks, I have already contacted.

totorus
11.07.2017, 18:58
I have already sent mail 3 months ago
I was told 2-3 weeks to resolve and I was not contacted anymore

GazzMan
14.07.2017, 08:53
as soon as we have the final answer which works for everyone we will post it here


Is there a solution to this please.

Vinny
14.07.2017, 11:52
Gazz, Your answer is on post 44 and 46, please take a look.