Skimmer causing PH probe interference

[mmarine1976]

I am using the AC3 controller with a DC 8 and have recently started having trouble with my PH. It started to drop about 3 weeks ago and has been reading steady at 7.63 for about a week. I tried recalibrating several time but no change. All my chemical test have been 8.1-2. I finally checked my ph by testouing it in a cup of tank water and it was right on at 8.18. So I started looking for what could be the problem and have found that when I unplug my Tunze Skimmer my ph will read OK. As soon as i plug my skimmer back in my ph drops about .5. I checked and can't find any stray current in the tank, I tried plugging the skimmer into another outlet, and I have even put a grounding probe in the tank and still no luck. Any suggestions on what I can do to fix this would be appreciated. I am also posting this in the Neptune forum.
Thanks,
mike

 

[rvitko]

I really wouldn't have an answer for this. I use a Tunze pH controller and several Tunze pumps including a 9010 skimmer and I cannot replicate this with my controller. I do not use any sort of ground. The Tunze electrode is a refillable glass/platinum electrode.