Probe readings off

[KJoFan]

When I originally set up my Profilux 4 I calibrated the probes per the directions. I recently did a little re-configuring/organizing of electronics and had to unplug the probes from the unit and re-plug them in. Since the, pH and conductivity have not read accurately. Do I need to re-calibrate them? I'm not sure why they would lose their calibration just with an un-plug/re-plug...

 

[Support@GHLUSA]

Please define not reading accurately.

Did you re-route the cables, possibly along power cables, or higher current/draw DC cables?

I'd try to re-seat the plugs and cables, make sure you have no kinks and tight corners, see if re-routing the cables will effect the readings.

 

[KJoFan]

Conductivity was reading 34-35 previously, which is accurate when measured against my refractometer, now it reads 30. As for pH it was reading 7.7-7.8 which was accurate and now reads 10.8 or so pretty consistently. It has read nothing below 10 since it was plugged back in.

They may be a bit closer to higher current cables, but I don't think significantly so. However, I would have to really check to see for sure tonight.

 

[Support@GHLUSA]

That is definitively odd, and not normal. Did you extend the cables?
Something is impacting the readings, check your cable routing, cable fastening, and plug configuration.

 

[KJoFan]

No cable extension. I will double check the seating of the cables and routing. It's possible they are closer to some other power cords than they were before. Maybe that's making the difference. I just didn't think they should lose calibration just from unplugging/re-plugging them in. The probes themselves were never out of the water or anything.

I'll give it all the once over and see where to go from there. Thanks for the input!

 

[Support@GHLUSA]

I just didn't think they should lose calibration just from unplugging/re-plugging them in. The probes themselves were never out of the water or anything.

I'll give it all the once over and see where to go from there. Thanks for the input!

You're correct - that doesn't happen. Calibration is stored in the device, not the probe. There is a signal that is being sent to probe, signal changes based on what the probe is reading, and returns changed signal. If there is interference in the physical wire, the signal could be skewed.

In data(network), we don't run data or signal wires parallel to power, we run them perpendicular. less chance of interference, cross talk, signal disturbance.

 

[KJoFan]

The only thing I can think of is that the probe wires might be closer to the power cord for the controller itself than it was before. Hopefully that is the case and it's an easy fix.

 

[KJoFan]

Turns out the pH probe was plugged into the wrong port, so that is fixed. I re-seated the conductivity probe but it's still reading low. It's always been a little lower than my refractometer reads, but is just worse now.

Is the conductivity probe just not that reliable?

 

[Support@GHLUSA]

Turns out the pH probe was plugged into the wrong port, so that is fixed. I re-seated the conductivity probe but it's still reading low. It's always been a little lower than my refractometer reads, but is just worse now.

Is the conductivity probe just not that reliable?

That'll do it every time.
They are reliable, however they are very susceptible to drifting once they either get dirty, or air bubbles accumulate. I'd try to gently shake the probe to see if it'll change readings. The Conductivity probe really needs to be kept in a high flow, low micro-bubble area.

 

[KJoFan]

It is currently in a pretty low flow area of the sump. Would it be ok to move them all to a higher flow area?

 

[Support@GHLUSA]

It is currently in a pretty low flow area of the sump. Would it be ok to move them all to a higher flow area?

Yes, more flow, less change for stagnant reading, and less chance for growth on the probes that will drift the readings.

 

[KJoFan]

Yes, more flow, less change for stagnant reading, and less chance for growth on the probes that will drift the readings.

Ok. So, this weekend I will try to re-route the power cord for the controller itself away from the probe wires. That's the only power cord near them. And see about moving the entire set of probes to a new location in the sump with more flow. Thanks for the help so far!

 

[dr.fish]

sorry to hijack your post, just a question, is it possible to extend a ph prob wire without offsetting the reading?