ORP readings fluctuating.........

Ok, so my ORP reading is fluctuating wildly, in a mug of tank water though it is stable and accurate.(reads 290 ish)

What have I tried so far................

Tank water earthed through a titanium wire(checked for continuity too, to the earth on the house wiring).
Switched off everything electrical on the tank bar the Profilux.
Replaced the psu for the Profliux
Tried the probe in the main display
Disconnected the temp probe
Disconnected the pH probe
Disconnected the VorTech PAB box
Disconnected the battery back up on the VorTechs

Now if I unplug the comms lead from S1/S4 (which goes to my plugbar & then doser), the reading goes up to 260 ish and is relatively stable, I don't know what else to try, any ideas guys.

Thanks

In such cases we generally recommend to unplug one device after the other until the value stabilizes. We understood that this is the case when you unplug the Powerbar. So please connect the Powerbar again and unplug each device from the sockets until you have found the probably defective device.
Another reason could be that your power supply unit is not working properly anymore. Perhaps you have the possibility to try another one?

You can also try to turn the power connector of your power bar by 180° (not possible in all countries - depending on plug style)

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Originally Posted by Carolin

In such cases we generally recommend to unplug one device after the other until the value stabilizes. We understood that this is the case when you unplug the Powerbar.

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Although the value increases the reading doesn't fully stabilise, I see an increase in the ORP value when the plug bar is disconnected.

Quote:

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So please connect the Powerbar again and unplug each device from the sockets until you have found the probably defective device.

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I've now tried the above and the problem still persists.

Quote:

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Another reason could be that your power supply unit is not working properly anymore. Perhaps you have the possibility to try another one?

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I have a spare psu which I have tried on the PIII, I have also tried it on the doser and the problem is still apparent.

Quote:

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Originally Posted by Wirus

You can also try to turn the power connector of your power bar by 180° (not possible in all countries - depending on plug style)

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Hiya, not possible here in the UK, we have 3 pin plugs.


Any more ideas, thanks....

Is the illumination maybe the source of interferences?

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Originally Posted by Matthias

Is the illumination maybe the source of interferences?

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Hi Matthias, I don't believe it is the source, with everything switched off and unplugged the problem is still apparent.

For info I have a PIII, 3 pump doser, 6 socket digi plug bar (connected to S1/S4), 4 socket analogue bar (S5/S8) 2 simu spots, 1 simu stick (L1/L2 with a active driver), dimming T5's (L3/L4), plus the pH, temp & ORP probes.
I also have a PAB VorTech controller.

With all the equipment on the tank off, the plugs out of the plugbar so just the PIII powered the problem is still there.

And the lamps are off during your test? If not, please unpower also the lamps.

We had some cases in the past where ballasts or tubes or lamps caused this kind of problems.

Yes, the lights are off and unplugged, still the same.

so, the summary is this:

- you measure in a mug of water a stable value
- the value is fluctuating if the probe is in the tank - even when ALL equipment related to the tank is unplugged (unpowered)
- the AC/DC has been replaced already

?

Yes, correct,

I have measured the voltage in the water with a multimeter with the pH & ORP probes out of the water and get a zero reading, with either probe in the water I get a reading, I take it the probes send out a voltage to gain a reading for the Profilux.

Now this may have no bearing on the problem I have but if I put the probe in a mug of water, then put my finger in the mug with my other hand in the tank I get a small shock??
Don't ask how I found this out!!

sorry, I ran out of ideas

I can offer you that we check the equipment here on our test tank

but I am quite convinced that we won't be able to produce the same problems as you have, I still think there is a source of interferences somewhere in or nearby your tank

If I might interject here, I noticed two key points in this thread that are of interest.

1.) Disconnecting the Com lead from S1-4 seems to impact the results of the reading
2.) Shock occurs when connection is made from probe to sump/tank.

This makes me strongly suspect an electrical problem. I have in some cases, seen electrical outlets that were not grounded correctly, or wired strangely (Line and neutral reversed, open ground/earth, or some odd combination). In these instances current that would normally travel to ground may be going through un-intended equipment. My own experience is limited to North American power outlets however, this may differ in your location.

This can also occur if salt has contaminated outlets, allowing for weak amounts of current to flow where it shouldnt.

I think some further examination of the outlets where the Profilux and the power bar are connected is warranted. IE: are they both connected to the same circuit?

Does this problem still occur with the power bar connected, but with no devices connected to the power bar at all? What if you connect just the dosing pump?

Is there a Ground/Earth probe in the Tank/sump to capture stray voltage?

I had similar case with unearthed RS232 connector on a laptop and in particular the use of serial to USB adapters.

An old thread of mine but one that is still causing me headaches, lol.

But, I was browsing though some other threads and came across this....

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Originally Posted by Matthias

We found out that all issues with bad probe readings (in most cases redox, in rare cases pH and cond.) had been produced through other devices or bad probes, as far as I know all issues had been solved.
In my opinion an isolator is pointless, for this this reason the development and production (which costs a lot of money initially) hasn`t a high priority anymore at the moment.

This could help:
- if the probe is defective (too old) replace it
- if you have an ungrounded ProfiLux power supply the use of a grounded power supply may help to eliminate the interferences from the Tunze pumps (the latest ProfiLux are shipped with a grounded PSU as standard in order to get rid of problems with noise from 3rd party products)

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I have found that by grounding my Profilux, not on purpose but by having the USB lead connected to a PC which is grounded the fault goes away, so it looks like I need a grounded PSU to fix my fault.

Are you able to supply one guys or should I contact Steve here in the UK.

Thanks

ps, Steve will be pleased as I have borrowed his P3 to eliminate the unit, he can have it back now. (hopefully the PSU will fix my fault)


pps, as Matthias knows I am running VorTechs, so this could be the source of the 'noise'.

I think Steve has these PSUs as spare parts

Thanks Matthias, just a thought, does the new PSU actually ground the Profilux, or is it just the PSU that's grounded?

the PSU is grounded, and this ground is then connected over the DC-wire with the ProfiLux

Ok, thanks, I'll wait to get a new PSU and report back.

Quick update Matthias, the grounded PSU has fixed this.