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 :D


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 :D


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 :D

[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.

[craigwmiller]

After tuns of more troubleshooting I shutoff the main pump which (due to water level) shutoff the skimmer power... SAME PROBLEM.

So, then I removed everything else, and connected just the skimmer grounding pin to the outlet's grounding pin - same problem.

THEN, I took the ph probe into a glass of water (which I've done before), when isolated, no problem.

Then I added the grounding probe to that glass of water, instant difference...


All this on the phone with waynemah to help troubleshoot verbally through everything -- when he come out with:

"HEY! you remember last summer when we were fixing the check valve in your hot water tank, there was those sparks when the water lines touched??!!! Did you ever look into that further??"

bingo, I think the issue is that something ELSE is electrifying my ground, and the skimmer is then (possibly due to bad shielding or simply broken internally) taking the electrified ground and spreading it to the tank.


My wife is out now, back in about 30 minutes -- I'll start testing ground fault potentials when she is around to kick me if I touch the wrong thing... The thing that is causing the problem is probably draining some current to ground, which is a slightly higher potential (possibly just a few millivolts) that the tank is noticing.


As per my last post regarding a DC potential that I have in my system with the skimmer plugged in -- my thought now is that there is a DC short somewhere, and the power is coming IN the skimmer, not out the skimmer... As to why the grounding probe doesn't do anything could be that it's DC, and that's creating a magnetic field or small current via the skimmer that an AC leak would not. Again just ~160 millivolts here...


Thanks for all the input!! Back to you with news (hopefully that I've fixed it, I just hope the thing that is possibly causing me a small short or leak isn't my TV or something else expensive LOL)

[Baldy]

if you are having problems elsewhere in your house, id look into grounding problems with your house itself. check the main ground wire coming off your panel going to your water pipes (usually) for corrosion or other issues.

[craigwmiller]

Okay, time to stop testing and time for bed, but here's what I've found:


From outlets around the tank (far from the panel) the potential between Neutral & Ground is 0.0 -> 0.1 (sometimes, but it just bounces there for an instant so if you blink you'd think it was always 0.0VAC). But on some other circuits (mainly in the basement, close to the panel) the Neutral/Ground potential is up closer to 0.5VAC.

I found two outlets in the house are wired wrong (hot and neutral are reversed). They each only have very minor loads on them. Shutting down these two bad circuits (and their loads) didn't remove the 0.5VAC potential.


Another 2 outlets in the garage (single garage circuit) don't work at all - but their immediate upstream outlet works, so I'm thinking a loose connection inside either the last working or the first non-working outlet... I will check out the garage properly tomorrow when it's light out.


I have not tested quite all the outlets in the house yet - family sleeping, etc... there very likely may be another outlet with a load on it that is wired backwards feeding current incorrectly -- or heck, possibly feeding return current down the ground.


Never a dull moment :D

Craig

[craigwmiller]

Okay well I fixed the badly wired outlets, and the odd voltage potentials are cleared up - glad nothing bad happened from those.

My skimmer is still still causing an issue though, so after all of the troubleshooting not being able to find a specific problem somewhere else it must be the skimmer.

Last test, before I re-post a request for a pump to try/buy :D

I unplugged everything inside the water and then tested conductivity between the water and the plug pins, here's what I found:

Pump, 2x Heaters, ZEOvit pump:
Ground or Neutral or Hot (from cord) -vs- sump water... Infinite Ohms (perfect)

Skimmer:
Ground -vs- sump water... 20K Ohms
Neutral -vs- sump water... 15M Ohms
Hot -vs- sump water... 15M Ohms


15M Ohms is high, sure, but there is conductivity there. 20K is very low, considering there should be no conductivity where I was measuring.


I should have done some of this specific conduction testing earlier, but first time troubleshooting something this odd there are so many things to try.


At least I resolved the Hot/Neutral mixup on those two outlets!!!!!


Now, to replace the skimmer pump.


Thanks!
Craig

[Baldy]

How old is your house/electrical? I don't see how you could have any voltage across the neutral and ground at all unless either your picking up inductive voltage from another wire or the neutral isn't properly.bonded in your panel. If your comfortable opening it up, check the jumper/bus bar/screw that bonds the neutral bar in your panel to ground as well. Just another idea.