Redox probe

[68darius13]

Hi,

After calibration, when i put the probe in the tank, the redox probe's measurements up and down by about 30 and then starts dropping to around 80. It does not make any sense. I washed the probe and put into calibration solution after a while the measurements settle at the correct value of 220.

Is there a possibility that other probes are interfering with each other or could there be any other issues?

Regards Darius

[GHL Support]

Hi

For how long have you kept the redox probe in the tank?

I would wait some more time and observe how the value in the tank develops - the redox measurement sometimes needs up to one week until the value settles down at a stable/correct level.

[68darius13]

Hi,
I kept the probe in the tank for three days. I set the signal sensitivity filter to 1, the readings fluctuate by 20. When it was set at 5, it was fluctuating by 50/60. When i remove the probe from the aquarium and put it in a vessel with aquarium water, the readings stabilises and stays stable. I'm really puzzled.
Darius

[Matthias]

this sound like electric interferences - it seems a device is disturbing the signal of the probe

make a simple test: unconnect (not only switch off but unplug) all other devices (not the ProfiLux) until the reading remains constant, then you found the source of interference

[samwise]

Hi,

I have exactly the same problem with my redox probe. Clean and calibrates perfectly, readings are stable in any vessel of water except my aquarium. Swings 20-30 mV all the time. This started just suddenly couple of weeks ago.

I figured out also that there must be electric interference and tried unplugging all equipment. When all other equipment was unplugged readings stabilized around to expected value (379 mV), but there was no single equipment causing the interference. It seems that it doesn't matter what equipment I plug in, with 1-2 equipment readings swing 3-6 mV, with 3-5 equipments it swings 7-15mV and with all equipments 20-30mV.

So my question is that is there any known reason causing electrode to became generally too sensitive to electrical interference by age alone? Any other ideas how to get it working? Could you guys at GHL check whether electrode is really broken if I send it to you? It is only a bit over a year old.

[Matthias]

the redox (and pH) probe are very sensitive for electromagnetic noise and this becomes even worse with the age of the probe
a swing of 20-30mV would not concern me, but you can improve the readings if you make the signal filter stronger

a chemical probe like pH or redox works 6 ... 24 months, depending on the circumstances, for this reason we can only offer a limited warranty for chemical probes for 6 months
-> it makes no sense to send the probe to GHL

[samwise]

Ok, thanks. Signal filter is different thing from the calibration tolerance? Haven't seen that kind of an option anywhere, in which firmware version that should be found?

Sami

[Matthias]

yes
in 4.xx