Acros dying and no idea why....

[NeverlosT]

Impossible.

Mr Miata is saying that the problem isn't stray voltage, and that Low N and P are the cause, While JDA is saying that stray voltage could be the cause and that low N and P are not the cause.

yes possible. I agree with Mr Miata that low N and P, plus alk swing, are probably the cause of his coral issues. And I agree with JDA that the stray voltage likely is not helping things. I just don't agree with both of them that the other is NOT the problem.

 

[jda]

Even if you are unhappy with growth and even some color with limiting levels of N and P, this does not cause death. Look past N and P if you have detectable levels at all... they are just a distraction. Find my re-build thread and check that out - I have .1 and 1 to 3 ppb of P and no issues, but I do have much availability which is where they key is. Underfeeding and using chemical CAN be an issue since they cut back on availability, but if you are feeding well and not using any GFO, Lan Chloride, Organic Carbon, or the like, then you are good. Stripping available N and P is an issue even if you have higher residuals (residuals are not as good as availability). If you are using chemicals or media, then it is probably a good idea to stop. ...so just saying that numbers on a test kit are bad is not correct and too simple... dig deeper.

I get a volt or two of stray voltage, but I have learned to live with that.

 

[ryshark]

Yes, absolutely what others have said. DO NOT use that ground probe without the GFCI to interrupt it. You now have a constant current on your ground wire. Typicaly household wiring as you probably know have 3 wires, only 2 of which are meant to carry constant current and are insulated, the ground wire is not insulated, is exposed, and grounds and metal conduit/boxes, you name it. All this exposed wiring and connections carrying constant current is asking for a shock or a fire.

So with the grounding probe plugged into a GFCI outlet, then the ground wire is not carrying a constant current? But if it’s not in a gfci then the grounding wire is carrying constant current?
Also, does the grounding probe need to be plugged directly into the GFCI or can it go into an extension chord with multiple outlets or surge protector, or Apex set to constant ON?
Thanks, I’m thinking about buying a grounding probe now, but want to use it correctly.

 

[zachj7]

So with the grounding probe plugged into a GFCI outlet, then the ground wire is not carrying a constant current? But if it’s not in a gfci then the grounding wire is carrying constant current?
Also, does the grounding probe need to be plugged directly into the GFCI or can it go into an extension chord with multiple outlets or surge protector, or Apex set to constant ON?
Thanks, I’m thinking about buying a grounding probe now, but want to use it correctly.

A GFCI outlet is basically an overcurrent device, much like the breakers in your electrical panel, only the GFCI is only operating on ground current, not load current. So if it detects ground current (current should only be showing up on the other two wires) it means current is escaping somewhere where it shouldn't be, and it will trip. This is why GFCI is required in places in your home that would be near water.

So plug in the ground probe into the ground socket or wire it to ground (however yours needs to connect). As long as where you connect with the ground probe is "downstream" of a GFCI outlet (and assuming it's wired properly so that it goes thru the GFCI and not bypass it) it will function. So if current does start to flow on the ground wire, the GFCI will trip. Without a GFCI that ground current will just continue to flow unless it gets so large that it drives the load current carrying wires above the trip point of your house breakers.

Hopefully I've explained that well enough for you, sometimes I get carried away in my electrical engineer speak. I set up electrical protection equipment for a living, but on the transmission level (69kV-345kV) and investigate electrical faults.

 

[nereefpat]

So with the grounding probe plugged into a GFCI outlet, then the ground wire is not carrying a constant current?

If any equipment goes bad, sending voltage into the water, a GFCI will immediately trip if a ground probe is involved.

But if it’s not in a gfci then the grounding wire is carrying constant current?

A ground probe will be a path for any stray voltage in the tank to go to ground. But if there is no GFCI to trip, the electricity just keeps flowing.

A GFCI outlet is basically an overcurrent device, much like the breakers in your electrical panel, only the GFCI is only operating on ground current, not load current. So if it detects ground current (current should only be showing up on the other two wires) it means current is escaping somewhere where it shouldn't be, and it will trip.

GFCIs don't detect ground current. They sense the current on the hot side and the neutral side, and if those 2 are different, the GFCI trips, interrupting the fault.

 

[zachj7]

GFCIs don't detect ground current. They sense the current on the hot side and the neutral side, and if those 2 are different, the GFCI trips, interrupting the fault.

Absolutely correct, that is how the GFCI phsycially "detects" ground current, the unbalance. Unbalance = ground current in this case. Was just trying to explain the overarching concept. The ground current could be traveling anywhere in a fault, not necessarily taking the path through the outlet's ground wire, which is why it looks for that unbalance in the load wires. But in this case the grounding probe will direct that fault current to the ground wires for safety.

 

[Overfloater]

I think it's important to figure out whether these are AC or Dc pumps. It absolutely makes a difference.

If they're AC, the stray voltage is absolutely a problem. If they're DC, it's a multimeter problem that's causing that - the way they measure voltage just doesn't work correctly with the voltage induced by 'dc' motors.

Yes, the return pump is an AC Jebao unit. I am planning to replace this with a Vectra soon. I have installed the grounding probe and GFCI protection.

I also hooked my skimmer cup back up and it pulled about 1/2 gallon of skimmate in a few hours. It has since settled down. After installing the skimmer cup, GFCI, and grounding probe I am seeing some polyp extension again on my newest no name acro.

I still think the cause of the RTN was a quick increase in nutrients caused by dumping the skimmer cup into the sump. I noticed that most that began to RTN turned brown first. The stray voltage may play a part in why there has been no polyp extension for quite some time.

Still, the damage is done. Most acros are almost completely RTN'd and I will probably be trashing them soon. A few have survived unscathed. Time to rebuild.

Thank you everyone for the help.

 

[Isabel’s Hobby]

No, I have not. I checked my other tanks and one has 24V and the other 34V. Both tanks have nothing but lights, heater, and return pump.

From what I am reading it seems some stray voltage is to be expected varying based on how much equipment is installed.

This tank is not on a GFCI so I will be taking care of that shortly. In the mean time, I have installed a grounding probe and stray voltage now reads 0.

At this point, I have lost most of the acros in my tank. A few seem unaffected, as are my squamosa clam, jawbreaker mushrooms, and goniopora.

I'm not convinced the voltage was the issue for the rapid decline (I guess you would call it a crash at this point), however it may be the reason I have had such poor poly extension over the last several months.

I think it was caused by a rapid increase in nutrients due to dumping my skimmer cup into sump (cup was 1/2 full) and thereafter allowing the skimmer to drain into sump, even though I have chronically low nutrients and testing after the skimmer dump only showed 7ppb PO4.

How do you test voltage ?

 

[Rick5]

I have related questions. I asked our electrician to replace the outlet behind my tank with a GFCI outlet. I was told it wasn’t necessary because all of the outlets in the house are routed to a GFCI. Would you recommend adding a GFCI anyway? I am using a ground probe. Thanks