Stray voltage

[iceman86]

Anyone ever get stray voltage from a ph probe/controller? I've been trying to track down the stray voltage in my tank but something is weird. Last week I was getting 90 volts in my water. I managed to track it down to a faulty ATO float sensor. I pulled that guy out and the voltage dropped to 20. Sometimes it would even drop to 5-7 volts.

I've been monitoring my ph with a pin point monitor for a while but this past weekend I setup my profilux controller to help control my calcium reactor and have more safe controls for my tank.

I calibrated the profilux probe and put it in the calcium reactor and kept the pin point monitoring my tank. I set all my values on the profilux and everything looked great.

Next morning both numbers looked off and the pin point ph was bouncing around. I figured it was some sort of interference so I disconnected the profilux controller and the pin point numbers settled at the right ph. I then recalibrated the profilux and set it back up and everything looked good until today everything was messed up again.

I started tearing everything apart again and looking for the interference. I tested voltage and got 20 volts so I started unplugging everything and I came to the conclusion it was the profilux controller. I unplugged it and got 4 volts on the tank water.

I then plugged the controller back in without any probes and still got 4 volts. I plugged in the temp probe and voltage jumped to 6 volts. I then plugged in the ph probe and the voltage jumped to 20 volts. At this point I figured it was a faulty ph probe so I took it out and the voltage dropped to 6 volts. I took the probe from the pin point and plugged it into the profilux to test it and the voltage jumped back up to 20 volts so it's not a faulty probe.

Any idea what could be causing this?

[Frogger]

Have you tried grounding your tank?

[iceman86]

Originally Posted by Frogger

Have you tried grounding your tank?

No I haven't but wouldn't that be masking the problem instead of fixing it?

[mike31154]

How's your livestock, looking good? If so then there is no problem other than you chasing numbers measuring voltage in your tank water. Voltage up to about 40 is unlikely to give you a shock or harm you or your livestock. Anything metal in your water has the potential to introduce a measurable voltage. Even lights may induce voltage in the water, fluorescents being the most likely due to the electromagnetic field produced by the tubes.

Grounding the tank may not only mask the 'problem' but also make it worse, turning the static voltage you are measuring into current flowing to the ground probe. The only thing with an electrical cord in my tank are heaters and a small pump delivering water to my skimmer. If I need to know my pH, I use a test kit. Water movement is by EcoTech pumps with electric cord outside. I don't use a controller, so can't really advise on what may be up with your Profilux.

[GoFish]

What would be causing it? Perhaps everything
Could be "Magnetic induction" Had noticed the same issue in 2014 and discussed it HERE. Gets complicated. I no longer test for stray voltage, probably should but still don't know what to do about it

[iceman86]

Originally Posted by GoFish

What would be causing it? Perhaps everything
Could be "Magnetic induction" Had noticed the same issue in 2014 and discussed it HERE. Gets complicated. I no longer test for stray voltage, probably should but still don't know what to do about it

Lots of good info on that link but it's not stray or induced voltage from the pumps because they were all unplugged when I tested.

I don't think the voltage is enough to harm anything but I need that ph probe to stay calibrated and working properly to control my calcium reactor. I'm not sure if it's because the controller plug in only has 2 prongs but from the googling I've done it looks like that's the right plug in.

Another strange thing I noticed is when I hook up my laptop to the controller while everything was plugged in, the voltage dropped to 2 volts. That was with the laptop charger plugged into the laptop. If I unplug the laptop charger it's jumps back up to 20. Could it be because the laptop being connected to the controller has a 3 prong plug in and takes the voltage from the controller?

[iceman86]

Originally Posted by mike31154

How's your livestock, looking good? If so then there is no problem other than you chasing numbers measuring voltage in your tank water. Voltage up to about 40 is unlikely to give you a shock or harm you or your livestock. Anything metal in your water has the potential to introduce a measurable voltage. Even lights may induce voltage in the water, fluorescents being the most likely due to the electromagnetic field produced by the tubes.

Grounding the tank may not only mask the 'problem' but also make it worse, turning the static voltage you are measuring into current flowing to the ground probe. The only thing with an electrical cord in my tank are heaters and a small pump delivering water to my skimmer. If I need to know my pH, I use a test kit. Water movement is by EcoTech pumps with electric cord outside. I don't use a controller, so can't really advise on what may be up with your Profilux.

My livestock are all doing well but except some corals have been getting STN but hat's that's a whole different issue. I don't think this is stray voltage or induced voltage from pumps since everything was unplugged when I was testing except for the controller, temperature and ph probe.

I did noticed today that the plug in for the controller is only 2 prongs so (no ground?) Could that be the reason the ph probe is making the voltage jump?