Medication and ORP

[GillMeister]

OK. I know ORP isn't something we should pay much attention to but I'm seeing something weird, and it's worth sharing.

I started dosing Polyplab Medic on Friday and turned off all my carbon, UV, and skimming fltration. My limited understanding of ORP is that it's somehow tied to water quality. Higher ORP should indicate cleaner water.

With all of my filtration off why is my ORP over 450 and setting off alarms on my Apex? It drops 200 points right after I dose and then shoots right back to 450-460.

GllMeister is confused.

 

[Jay Hemdal Verified Community Expert]

My understanding is that it is a peroxide salt, so I would expect the ORP to rise, but I can’t explain the drop beforehand.
Jay

 

[Randy Holmes-Farley Verified Community Expert]

Some of us have long been confused why adding certain oxidizers, such as hydrogel peroxide, seems to lower ORP in reef aquaria. Chemically, it should not do that.

My best hypothesis is that it locally kills some bacteria where it is added, and they spill their low ORP internal contents into the water, reducing ORP. Is that really why? Don't know.

 

[GillMeister]

Some of us have long been confused why adding certain oxidizers, such as hydrogel peroxide, seems to lower ORP in reef aquaria. Chemically, it should not do that.

My best hypothesis is that it locally kills some bacteria where it is added, and they spill their low ORP internal contents into the water, reducing ORP. Is that really why? Don't know.

Makes sense, but doesn't explain the rapid rise immediately after dosing. My ORP usually does run high, around 420, but it's now over 450 when I really expected it to fall with the filtration turned off.

 

[GillMeister]

 

[Randy Holmes-Farley Verified Community Expert]

I can speculate a decent reason, but have no idea if it is true.

ORP is a very complex measure. It is likely primarily measuring the relative abundance of the different forms of iron or manganese, or maybe certain other redox active metals

Converting Ferrous iron to ferric iron, for example, raises ORP. But that doesn't necessarily happen instantly.

So maybe the initial drop was as I suggested, and then later, as the product is mixed in it no longer is locally killing bacteria, and is able to raise the ORP.

In any case, I do not see a definitive reason to expect different behavior or suspect a problem.

 

[Erick Armanii]

I’m perplexed in ORP readings and why higher orp readings equal better water quality.

My probe reads at 270 and when I do a water change it drops. Overall my tanks chemistry is spot on. What am I missing?

 

[Randy Holmes-Farley Verified Community Expert]

I’m perplexed in ORP readings and why higher orp readings equal better water quality.

My probe reads at 270 and when I do a water change it drops. Overall my tanks chemistry is spot on. What am I missing?

Higher ORP does NOT imply better water. That's a very long standing myth perpetrated by people who do not understand ORP.

new salt mixes often lower ORP, likely due to the specific forms of trace elements used (like low ORP ferrous iron) that are much more soluble than the higher ORP (more oxidized) forms (like ferric iron).

 

[GillMeister]

I see this statement about ORP and water quality everywhere. Here is a snippet from an article with a link:

The higher the oxidiser volume, the higher the breakdown which in turn leads to cleaner water. ORP measures this in millivolts (mv). The higher the ORP, the higher the chance of oxidation. It is not a direct indicator of bacteria count, more so the quality of water within the system. This means the higher the ORP, the cleaner the water.

Understanding ORP & SPS Colour

I was recently asked a question on Oxidisation Reduction Potential (ORP), why only "some" marine

www.reefanabolics.online

I realize there is a lot of disinformation out there and some of it might be an effort by 'experts' to dumb down the topic for those of us without a chemistry background.

 

[Randy Holmes-Farley Verified Community Expert]

I see this statement about ORP and water quality everywhere. Here is a snippet from an article with a link:

The higher the oxidiser volume, the higher the breakdown which in turn leads to cleaner water. ORP measures this in millivolts (mv). The higher the ORP, the higher the chance of oxidation. It is not a direct indicator of bacteria count, more so the quality of water within the system. This means the higher the ORP, the cleaner the water.

Understanding ORP & SPS Colour

I was recently asked a question on Oxidisation Reduction Potential (ORP), why only "some" marine

www.reefanabolics.online

I realize there is a lot of disinformation out there and some of it might be an effort by 'experts' to dumb down the topic for those of us without a chemistry background.

That is exactly the kind of article I mean that perpetrates the myth that higher ORP means " better" water.