Thoughts On Stray Voltage

[Josh]

Basically what I would do is add a ground probe, hook it up to a gfi on a different electrical circuit and have a light hooked into the gfi. Come downstairs light is on, good to go. Come downstairs light is off, possibly gfi trip, investigate issue.

 

[Salty Cracker]

Here's an older thread that I started that covers some of the same ground (no pun intended):

http://thefragtank.ca/community/thr...tage-etc-for-the-electrically-ungifted.10623/

Definitely a difficult topic to get one's head around for those who are not electrically inclined. In my old 120 I definitely had stray current I think from my DIY T5s and reflectors, and I had HLLE issues in a couple of tangs and angels... not definitive by any stretch but I think there is a possible correlation there for sure, as all my fish had clean water and a great diet.

Interesting about your thoughts on current and SPS dying Salty, in some parts of the ocean they actually use current to help stimulate coral growth... but maybe you had way to much and its not comparable in such a small enclosed system vs. the vastness of the ocean!

https://www.globalcoral.org/to-rebuild-coral-reefs-quickly-just-add-electricity/

It's weird that I missed that old thread, although likely I was following along and just didn't have anything useful to add to it.

I will say this, on the old tank almost every tang or angel got HLLE, like every single one of them, so I had been more diligent on carbon dust (one of the possible culprits), but now I'm wondering if the ~5V that was floating around the last tank had issues, since I still run carbon non-stop (all I added to this setup is a mesh collection bag on the output of the reactor). So swapping the old AC pumps may well have been the issue, since I've actually added more heaters and little pumps to this tank, but I "upgraded" to a DC return pump. I have 2 of the fish that were affected, still to this day, and both of them have not gotten any worse, and have recovered somewhat. Seeing the .5V in the tank reinforces the theory of voltage and fish issues.

Previously I had to have a cut on my hand or finger to feel the buzz of the current. When this tank went bad it was a full on shock. Not that buzz you get from accidentally touching mains, it was more of a discharge snap. So -possibly- the tank was acting like a capacitor(?) and holding more charge than just the pump current would supply?

I know for sure that when I removed the pump, the tank started to recover within 12 hours. The not-quite-dead-but-still-not-good smell that filled the house was decreased by a quantitative amount. in 24 hours it was gone, and the sludge in the skimmer took on a whole new consistency. (Good god that stuff smells). I mean I had suspected my makeup water, because I got a reading of "2" on the TDS meter (DI resin was exhausted), but after relpacing everything in the RO/DI the tank was still stinking/dying.

 

[Salty Cracker]

Most multimeters have 10megaohms of impedance so no ground probe effect. an old school analog meter would give some current flow

Ahhh, okay. They should be pretty easy to source on ali or something like that, or is it possible to remove the impedance on a modern meter? I mean, that doesn't sound like a good idea for general use, but for this specific application? What is the purpose of the high impedance...protection or does it serve a purpose on the reading?

 

[Pistol]

The high impedance is so the meter doesn't put any load on the circuit being tested, especially some sensitive electronics that could be destroyed by an analog meters load on the circuit.

 

[TheGreatWave]

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[Josh]

If you really wanted a good option, wire a 120v relay to a dry set of contacts on the breakout box for neptune and program the output as an alarm, just make sure you either use the normally closed contacts. Basically any time the power is on the contacts are open, power shuts off aka during gfi trip the contacts would close an alarm to your neptune apex.