Skimmer Voltage/ground Leak, new pump? Vertex IN-80/100

[craigwmiller]

It seems my pump has some voltage leak, though I can't specifically detect what it exactly is... I can't detect anything with a volt meter, but when the skimmer is running my pH probe is down about 1.5-2 ph when electrically grounded to my PC/etc. I unplug the skimmer, and right back up to normal.

Maybe someone has an idea on how I can use a volt meter to accurately find this leak? could be a grounding problem maybe, or stray voltage, or something?


And if someone has a Vertex pump for a IN-80 or IN-100 skimmer that might be just as easy

[Baldy]

Use a voltmeter on ac volts. Put one probe the ground terminal of a wall plug or extension ford that is grounded (the round terminal on the wall plug) and put the other probe of the voltmeter in the water. If it shows voltage that disappears when you unplug the skimmer, then its the pump. make sure you get good contact on the plugs ground slot, it can be tricky as there isn't metal contacts all the way around the hole.

Please don't fix the problem with a ground probe. I'm going to get flack for saying this bit a ground probe is just a bandaid to a bigger problem. It takes stray voltage and turns it into current through the water.

[craigwmiller]

There is no stray voltage that I can detect. I get 0.00 volts from the sump or DT to several different circuits' grounding pins.

I *do* normally have a grounding probe on my system -- but I also have 4 GFCI circuits powering the system, (I would never ground a conductive system without upstream GFCI protection). I also tested 0.00 volts and 0.00 amps before I put the grounding probe into the system. As for a 'bandaid' -- it should not be considered a bandaid ever, if one has > 0.00 volts of stray voltage, the solution is to fix the problem first.... The grounding probe will help save your life by causing your GFCI to trip should any future problem occur. (if you put in a grounding probe without GFCI, current will flow freely, and this is very dangerous)

(but please note the voltage & current testing was done with the grounding probe disconnected)


The issue I am having is odd and though it is directly related to my skimmer, my pH probe is the only thing that seems to notice it, and only when the system is grounded via usb to my PC. Even though the water is also grounded via a grounding probe (or not).

I'm going to continue my measurements -- but 0 means 0 in my books, and if I can't find anything, there might not be anything to fix -- possibly I have some static generated via the usb connection or something that is causing me grief -- so maybe a usb isolator??!!

[Baldy]

if you read 0 and there is no other path to ground (maybe try disconnecting the usb to your computer before testing if you havent tried that already), then it wouldnt be stray voltage.

You seem to know more than i assumed about electricity. I am a 4th year electrician and i find a lot of people, not just in the aquarium hobby, that dont know much about it. looks like youve got your bases covered. if you test in the future, you could use your ground probe out of the water as a point to measure voltage from.

about the gfi, i dont use them because i know how sensitive they can be. to the point of being over sensitive. It only takes 6mA of current difference between the hot and neutral for a gfi to trip. i like the peace of mind knowing that it wont trip and take out my whole systems power when i leave for the day. next setup i do though will have redundant return pumps on 2 different circuits that will be gfi protected.

[craigwmiller]

Thanks for the props on the knowledge My background includes network (primary) and electronics engineering, and practically running a datacenter with massive electrical requirements, gensets, specialty grounding, well you know

And yeah I had the same nervousness from GFCI, but the safety was too important to me -- so I installed 4 circuits, downstream from UPS backup, with all the equipment and pumps spread among each circuit - so the tank could sustain itself for at least a couple days with some circuits tripping, so long as not all of them go out... current project is to add to that an automated e-mail & text when all power goes out to the tank (via breaker, or downstream gfci)... all this is at least as much fun for me than the actual reef keeping


Now to the problem at hand, there is undoubtedly something up with the skimmer -- but I'm going on a trip in a week so I don't want to change anything in the tank while I'm not around to monitor... but due to the same thing, I will not have pH monitored while I'm away (not the end of the world).

I will do some testing though with it -- I'm thinking a separate bucket of water with the skimmer doing it's thing and the pH probe - to at least eliminate the interaction between the skimmer and something else or the pH probe and something else... full test, another separate circuit, etc.


Now, another question for you (or anyone) related to testing electrical... Will a conductivity test offer any insight here? pH uses reference voltages, right?, and if there is some resistance to ground between different devices, things could be strange... Possibly I'm thinking that the ground from the skimmer is somehow exposed (but if just ground exposed, not a real issue), but perhaps with a higher resistance -- just brainstorming as I'm typing


Cheers!

[Baldy]

I don't know enough about conductivity to comment nor do I know anythinabout how ph probes work. I can help with the grounding bit but the test is a bit beyond my knowledge

[Baldy]

just a stab in the dark here, but is there any chance that the aeration from the skimmer is affecting the readings?

[KrazyKuch]

a conductivity test is more or less the same as a salinity test or tds, ph probe is basically a device that generates a voltage....A ph meter is just a high impedance op-amp(amplifier) the voltage is generated by the probe itself (mV)...How close is the probe to the skimmers output????

[craigwmiller]

Good thought possibly static/etc from the bubble velocity/etc...

so I just tried it - I removed the intake venturi from the pump (stopping all air from being drawn in), and let it run a few minutes to calm down -- no difference.

I also then tried moving the PH probe around the sump (and into the display) to rule out distance from electromagnetic fields/etc -- nothing.


I think I've narrowed this down to an induced voltage from the EMF from the pump feeding the skimmer. With my volt meter in DCV mode, I have a potential of 167 millivolts from the tank to ground with the skimmer running, and 0 millivolts with the skimmer unplugged. True this EMF isn't creating DCV, but there is still some detectable as a 'potential' so the skimmer motor is very likely unshielded.

I've done conductivity testing from the tank water through to all prongs of the skimmer cord (and between them) and the impedance is at least 2 million ohms - so let's say there's no connection -- so this must be EMF.

Now, I could definitely just be talking out my A** and chasing a solution that makes sense in my mind (after all the troubleshooting), but it would seem this explains it best (in the absence of a physical leak from any of the 3 conductors to the tank - as identified by conductivity).


Ordering a new skimmer me thinks. Or at least a new pump.

[ScubaSteve]

My gut says noise from EMF, especially if its a conductivity probe (I'm a thusly fairly confident). How close is it to the pump? Can you try putting the probe in the display far away from the pump (or anything else that may cause a similar effect)? If its voltage leak, you'll probably still see the issue. If its EMF related, it should disappear.