GHL Oxygen Probe

[Piercey_20]

Hey all,

I'm just wondering if anyone has any experience with the GHL oxygen probe? I can't seem to get a good reading after Multiple calibrations. I have the temp and Cond probes selected and calibrated. But my oxygen is always reading anywhere from 112% -125%. I'm not bubbling any air at this point because the DO% never gets below 100%. I got a loan of a research labs DO meter and it reads the DO as 92-98%.


Any help would be appreciated!!

 

[vangvace]

I'm not sure if @Lasse has experience with this probe, but he would be my best guess.

 

[Lasse]

I'm not sure if @Lasse has experience with this probe, but he would be my best guess.

Its a good guess - yes i have got some grey hairs from it but - at last get it to work rather well :D

First - do the calibration exactly the way it is described in the manuals. The most important is to do the zero calibration and after that connect the oxygen BNC to the card and wait 30 minutes before the air calibration starts. For the Air calibarition - I place the electrode around 1 cm above the moving surface (needs 100 % humidity air) In this step - I also take my profilux temp probe and let it hang just beside the oxygen sensor. The probe I use as temp compensation. I let both probes adapt for 30 minutes and when asked for air temp - I read of the temp probe.

When I have to chose what methode I will use for temp compensation and salinity compensation - I use automatically temp compensation with my temp probe but for the salinity compensation - I use manual mode and the salinity I have mostly.

The oxygen probe needs some maintenance too - please see here

You need also to have the probe in a in a part of the aquarium /sump where the water has a certain velocity because these type of electrodes consume oxygen.

Good luck

Sincerely Lasse

 

[Piercey_20]

Thanks! We had no idea where to put the probe for the 30 mins. Tried both in the water and out of the water. Haven't tried the 1cm above yet. Started off getting high DO readings and after calibrations today I'm getting like 60-70%. I'll try what you've got done tomorrow! Thanks again!