ORP and Stray Voltage: Weird Experience

[James MacFarlane]

Hello all!


I want to share a weird series of events with my fellow reefers!

Last night at about 8 pm, I fed my fish and sat down for a movie. All was well, everything looked great!

2.5 hours later (Blade Runner 2049), after the movie, I took my usual glance in the tank before bed. To my horror, two of my healthiest colonies, a miyagi tort and a blue stag horn had RTN. In that small amount of time.

Tested my parameters, everything was normal, usual range. Out of desperation, I went and grabbed an extra grounding probe that I’d never gotten around to installing. Installed it, dipped the Miyagi in witch hazel, added a poly pad and went to bed. Woke up to a complete halt to the RTN.

Fast forward to today and I’m looking through my Apex history to see if anything was off during the time of the RTN. As you can see in the attached image, ORP appeared to completely crash at 8:30, right around the time the tissue loss would have started.............

What do you guys think? Could there be a correlation between ORP and stray voltage? Could stray voltage interfere with the ORP probe itself, causing the “crash” in ORP? This is all assuming that stray voltage was the issue and that the probe corrected the issue.

Just seems like a weird coincidence and I wanted to share.

 

[Randy Holmes-Farley]

Do you know where exactly in that curve you added the ground probe?

 

[Admann]

I don't understand why stray voltage wouldn't affect any low voltage driven sensor. Any electricians or SCADA techs out there that know why it would or wouldn't.

 

[Randy Holmes-Farley]

I don't understand why stray voltage wouldn't affect any low voltage driven sensor. Any electricians or SCADA techs out there that know why it would or wouldn't.

I don’t understand the question exactly, or even what exactly you are intending by stray voltage.

ground probes can mess with electrical devices that rely on their own reference probe. A pH meter and an ORP probe fall into this category. Google ground loop and pH and you can see the potential concern,

 

[LARedstickreefer]

Haha, SCADA. That’s the first time I’ve seen it mentioned on a reef forum! I used to manage our scada system at my old electric utility.

Ive never understood what ground probes, in tanks, are supposed to be doing. If there is a fault, a breaker should trip. If there is “stray” voltage, a ground probe now is providing a real path for current to flow. If it’s not enough to trip a breaker, what is it accomplishing? I guess a GFCI should trip and knock the entire tank offline...

Any electric device in or near your tank will produce a field that extends into your tank. A ground probe is going to cause current to flow, which to me, would be bad.

 

[Randy Holmes-Farley]

I used a ground probe so that a GFCI would trip before I stuck my hand in the tank and completed the loop myself . I had a number of heaters and other devices fail over the years and GFCI would tell me when that happened. I used about a dozen different GFCI to isolate devices when it trips

 

[LARedstickreefer]

I used a ground probe so that a GFCI would trip before I stuck my hand in the tank and completed the loop myself . I had a number of heaters and other devices fail over the years and GFCI would tell me when that happened. I used about a dozen different GFCI to isolate devices when it trips

I need to get one of those multi gfci deals so that I can isolate the device instead of knock the whole tank offline.

I think I’ll pull out my DMM today to see what level of current is flowing through the ground probe during normal operation.

 

[Admann]

Haha, SCADA. That’s the first time I’ve seen it mentioned on a reef forum! I used to manage our scada system at my old electric utility.

Supervisory Control And Data Acquisition, we used it offshore for control of our offshore facilities. I wish APEX was as easy to use. I digress, I own an APEX just have to get the tank ready. New build thread starting soon.

 

[James MacFarlane]

Do you know where exactly in that curve you added the ground probe?

Hello Randy,
I marked the attached image with a blue line.

To all - To clarify I’m not making any claims, btw, I actually have no idea what happened. Just seemed like a weird series of events. That may or may not be related.

I’m thrilled that whatever happened, the RTN stopped as abruptly as it began.

 

[LARedstickreefer]

My guess would be the witch hazel dip that stopped the rtn. Rtn is believed to be bacteria in many cases.

 

[corihill92]

I'd imagine that the stray voltage could affect the probe. I've had voltage issues but I dont use an ORP probe on my apex so I'm bot positive.

 

[jccaclimber]

I’ve seen ORP dips and log curve sort of recoveries intermittently when doing things like adding a cube of mysis. I assume it’s real as I’ve seen it on multiple tanks. The odd thing is that it doesn’t alway seem to happen.
No clue on what started or stopped your RTN, but I am curious what sort of current is passing through your probe.

 

[James MacFarlane]

I’ve seen ORP dips and log curve sort of recoveries intermittently when doing things like adding a cube of mysis. I assume it’s real as I’ve seen it on multiple tanks. The odd thing is that it doesn’t alway seem to happen.
No clue on what started or stopped your RTN, but I am curious what sort of current is passing through your probe.

Me too. How can I find out?

 

[jccaclimber]

Put a DMM reading current in series with the probe, or remove the probe, ground one DMM lead, and dip the other in the tank.
The other thing you can do is set the DMM to voltage (probably AC IME), ground one lead, and put the other in the tank (also with the ground robe removed). If you find much stray voltage just start unplugging devices until you find the one causing it (reading will drop).

 

[Randy Holmes-Farley]

Hello Randy,
I marked the attached image with a blue line.

To all - To clarify I’m not making any claims, btw, I actually have no idea what happened. Just seemed like a weird series of events. That may or may not be related.

I’m thrilled that whatever happened, the RTN stopped as abruptly as it began.

based on the timing of the addition of the ground, it seems unlikely to be related to the ORP readings

 

[smacrophylia]

based on the timing of the addition of the ground, it seems unlikely to be related to the ORP readings

Hey sorry for the late reply lol. I hope this finds you and I hope you have the time to help. I appreciate you. I had an issue with my tank in early-mid April. lighting schedule starts at 9AM came home from work at 12-1pm and found my tank cloudy with flesh from rtn acros and a bunch of unhappy corals (hanging on by a thread as it seemed)zoas,lps,sps.

The day before, I played with my lighting settings on my radions. And when I found the cloudy tank there was a turbo snail sleeping on the apex pmk sensor. Yes, directly on top. I assumed that I had activated the new lighting settings at 100% strength which would be about double what I had originally set it at which would obviously shock everything. I assumed this was a lighting mishap because my par readings for the day were 0. The sps that were still surviving were bleached and struggling. Actually all corals including torches and hammers were bleached nearly translucent.
This is what led me to believe that I cooked everything under the lights for a little over 3 hours.

BIG LOSSES.
Water Params were stable as always basic flawless(for me) parameters. Present stable nutrients and 8-9 alk

I blamed the snail for blocking my 900par reading on my apex that would have alerted me to shut the lights off or go home and fix the settings.

Started dosing acroglow and flatworm stop to help acros recover worked really REALLY well over the next month.

Yesterday I threw 3 cubes of mysis in and took a nap with my daughter..two hours later I woke up to hundreds of zoas all closed, shriveled trachy,lobo, blastos, and pale struggling sps.

Immediately I tested. 8.2 alk 0.05 p 9.6 n
What kind of bullcrap is that?!?

I found a thread where you listed potential causes of tank crashes and the very last item listed was I believe and I’m not quoting stray voltage. Then I remembered a few months ago the back wall pump of my Red Sea failing causing smoke to pour out of the back area of the overflow. (This was a bit before the first “tank crash” maybe a month or two) I unplugged the pump and kept life rolling. Is the old Red Sea tank and associated equipment finally failing and causing electrical danger?

I attached the first “crash” shown in the lowest point of the April orp reading

Also I attached the orp reading from yesterday showing the drop. I have no evidence that voltage caused the coral death or decline but other than that I am truly lost because the water tests come back (chefs kiss)

I have a pack of icp tests coming asap to hopefully rule out other possibilities but I have the stand setup for my new waterbox and I’m ready to take a sledgehammer to the Red Sea and move on.

Thank you for reading if you did and I appreciate all that you do

 

[BeanAnimal]

Put a DMM reading current in series with the probe, or remove the probe, ground one DMM lead, and dip the other in the tank.
The other thing you can do is set the DMM to voltage (probably AC IME), ground one lead, and put the other in the tank (also with the ground robe removed). If you find much stray voltage just start unplugging devices until you find the one causing it (reading will drop).

A DMM in this setup will often read an incorrect voltage and without a current reference is meaningless, as it is almost certainly an induced voltage unless it is at or close to full lime voltage.

 

[BeanAnimal]

based on the timing of the addition of the ground, it seems unlikely to be related to the ORP readings

I would agree with this assesment.

 

[BeanAnimal]

If there is a fault, a breaker should trip. If there is “stray” voltage, a ground probe now is providing a real path for current to flow. If it’s not enough to trip a breaker, what is it accomplishing? I guess a GFCI should trip and knock the entire tank offline...

just to be clear for those following along.

Circuit breakers are NOT meant to directly protect you, they are there to protect the wire at its rated current that is deadly for you. The GFCI is added to protect you and trips at a tiny current and is meant to protect you.