pH probe problems

[Kenfuzed]

Anyone ever have a pH probe pick up interference and cause very high readings?

Just received a brand new RK2 w/ optional Pinpoint pH probe. Calibrated per instructions, but when I put the probe in the sump I get a reading of 11.55. When I remove the probe and place in a cup of tank water (same water) I get a reading of 8.21. I searched around for any pumps leaking voltage into the water by turning one off at a time, nothing changed. Started turning lights off, and my EVC MH when off dropped the reading down to 8.65, and one of my IceCap MH ballasts took the reading down to 8.3 when turned off as well. Strangely the other 2 IceCap MH ballasts which are identical make no difference. I've tried changing plugs around, running external ground wires, nothing seems to work.

The other thing I find odd is I just got rid of my Neptune ACII controller to be able to use any ballast and that unit never had any issue with the pH probe. My handheld pH pen meter has no problem either.

Could there be something wrong with the probe?

 

[Mchava]

I had the same issues with mine, what I did was change the power plug to a diffrent power strip and that helped not sure if this would work for you.

 

[xinumaster]

I had the same problem with my acjr before. everytime my power compact lighting (which is connected to my dc8) turns on my ph and temp would read errorously, so what I did to fix was I removed my pc from the dc8 and connected it to an x10 instead.

 

[Kenfuzed]

I've yet to connect anything to the controller's power strip, just have the pH probe and temp probe connected. All the the lights and pumps are still on external timers for now. It seems as though a signal or interference is traveling through the water, because when you take a cup of water out of the tank and place the probe in it the reading is suddenly okay.

I thought only X10 had problems like these. :mad2:

 

[Kenfuzed]

Things get stranger. I removed my ground probe and the pH reading dropped to around 8.6 but not down to normal. I'm thinking the pH probe could be passing current back into the water since my lights are not in contact with the water.

 

[saltyESQ]

I had a grounding probe that threw back the current into the water. Hurt really bad, until I decided to take the grounding probe out and never felt electricity again

 

[Kenfuzed]

I've never been shocked, yet it seems like current is passing through the controller and pH probe when the tank is grounded. My little pen meter doesn't pick up any difference when the tank is grounded, just the one connected to this controller.