Dropping ORP levels

[Pufferlover95]

Recently over the past few days I’ve been having times when the ORP probe in my reef tank starts to steadily decline despite me not being home and doing anything to the tank. I do not use ozone and I don’t typically have concern over the fluctuation until it goes outside of normal ranges. I dose NOPOX steadily throughout the day and don’t see any major changes to parameters when the doses drop.

I’m paranoid when I’m at work because the last time I had a major spike in my ORP I was at work and I came home to 90% of my fish dead. I’ve been lucky enough to have eyes on my tank now whenever these levels have began dropping, and from a fish perspective nothing has changed (nobody has died).

Anybody have any ideas as to what might be causing this?

 

[Randy Holmes-Farley Verified Community Expert]

A rapid ORP drop often means something is on the probe, such as a snail, etc.

 

[Pufferlover95]

A rapid ORP drop often means something is on the probe, such as a snail, etc.

With something like fish/invert deaths, you’d expect a rapid RISE in ORP?

 

[Randy Holmes-Farley Verified Community Expert]

With something like fish/invert deaths, you’d expect a rapid RISE in ORP?

No, a drop, but that drop seems too sudden to me.

 

[Pufferlover95]

No, a drop, but that drop seems too sudden to me.

This is now, still dropping:

What do you consider “sudden” versus more gradual?

 

[Randy Holmes-Farley Verified Community Expert]

The sharp start to the drop (instantaneous slope change) does not appear to me to reflect a change in the water unless you started dosing a low ORP chemical there.

I’d pull the probe out and clean it.

 

[Randy Holmes-Farley Verified Community Expert]

What killed the fish in your earlier experience? The orp drop might have been caused by the same thing that killed the fish, not from the dead fish.

 

[Pufferlover95]

What killed the fish in your earlier experience? The orp drop might have been caused by the same thing that killed the fish, not from the dead fish.

Most likely a NOPOX overdose. I hand dosed early that AM and left for work. I didn’t know how much exactly I added. It’s now on a dosing pump and my net water volume is more properly calculated than it was prior.

 

[Pufferlover95]

The sharp start to the drop (instantaneous slope change) does not appear to me to reflect a change in the water unless you started dosing a low ORP chemical there.

I’d pull the probe out and clean it.

Is Citric acid ok to use on that probe? I don’t know the in-and-out of how the probe is calibrated so I didn’t want to assume CA was safe.

 

[piranhaman00]

The solution is the stop monitoring orp it means nothing

 

[Randy Holmes-Farley Verified Community Expert]

Is Citric acid ok to use on that probe? I don’t know the in-and-out of how the probe is calibrated so I didn’t want to assume CA was safe.

Yes.