Can Someone Help Me Understand Redox Potential?

[Jennywren]

HI guys!

I've seen some murmurings on the internet recently about the importance of positive cations and redox potential in the aquarium, and I could really use some help understanding what it's all about! In short:

• What do these terms mean?
• Why are they important/what is their significance to fish
• How does one test for or adjust them?

Thanks so much!

 

[max h]

I looked it up real quick, the explanation and terminology are way above me, but it's used in saltwater home pools for sanitation. Basically for a home with a backyard pool with a salt water system installed, you add Sodium Chloride to the water. As the water circulates through a reactor cell in the system chlorine is produced to kill the pathogens in the water. Over time those reactor cells need cleaning and replacing. I worked in and around pools for many years, my personal preference would be to use regular chlorine in the pool, even at the higher end of 2 ppm of chlorine in recreational pools it's harmless to humans. The burning that people feel in the eyes is not do to high chlorine levels, it's normally the ph being off. I worked for years in pools that had chlorine levels between 2-4ppm due to the nature of the work, the amount of people, and equipment we had in the pool.

 

[Jennywren]

I looked it up real quick,...it's used in saltwater home pools for sanitation...

Hmmmm....I'm guessing it has slightly different significance/application in the aquarium world lol.

There are only 13 hits for the term when I search the forums, but maybe some of those folks can help:
@Rivieraneo @Dolfan @ @ @ @Peterpiper @pepetj

 

[max h]

I all has to do with chemicals and electrons. I'm better with night vision devices and water survival things.

 

[iZaO Jnr]

Okay, chemical science and botanist here. Brace yourself.

Redox potential basically means the reduction and oxidation ability of a solution. A good example of how this works is in batteries, so I'll go along with that example and you can apply it to your situation.
Reduction potential, or a reducing compound is able to donate one or more electrons, while a oxidizing compound receives one or more electrons.

Please let me note at this point, none of that matters for your tank's purposes, believe me. Basically, a redox potential to allows for a chemical reaction to occur, and for electric current (small and insignificant in the tank but a high potential is useful in batteries).
Furthermore, in your tank, the redox potential won't really tell you much about the reactions going on, which is why we use kH and gH readings to understand the presence of certain minerals in the water.

It is these minerals (calcium and magnesium foremost among others) that fish use to regulate water content in their bodies (we drink, they control their osmotic potential). This is exactly what vastly separates freshwater and saltwater species of any life.

Lastly, testing for it is vastly unnecessary, with even large marine aquariums not having much need for it. The only knowledge I have of being able to test something akin to redox potential Is testing the water's conductivity, which once more is a very expensive and 'overkill' means for information about your water. As for adjusting, don't. There are other ways to regulate your aquariums water quality, all of which will take care if whatever your concerns may be.

...

I did try to keep this as simple as possible, as it can go into excruciating detail. Unless you're highly interested (if so ask), I would rather suggest you read up on kH and gH rather... Much more pertinent to the aquarium.


Edit: Sorry for funky grammar... Autocorrect seems to not like me @ 4am

 

[KimberlyG]

Okay, chemical science and botanist here. Brace yourself.

Redox potential basically means the reduction and oxidation ability of a solution. A good example of how this works is in batteries, so I'll go along with that example and you can apply it to your situation.
Reduction potential, or a reducing compound is able to donate one or more electrons, while a oxidizing compound receives one or more electrons.

Please let me note at this point, none of that matters for your tank's purposes, believe me. Basically, a redox potential to allows for a chemical reaction to occur, and for electric current (small and insignificant in the tank but a high potential is useful in batteries).
Furthermore, in your tank, the redox potential won't really tell you much about the reactions going on, which is why we use kH and gH readings to understand the presence of certain minerals in the water.

It is these minerals (calcium and magnesium foremost among others) that fish use to regulate water content in their bodies (we drink, they control their osmotic potential). This is exactly what vastly separates freshwater and saltwater species of any life.

Lastly, testing for it is vastly unnecessary, with even large marine aquariums not having much need for it. The only knowledge I have of being able to test something akin to redox potential Is testing the water's conductivity, which once more is a very expensive and 'overkill' means for information about your water. As for adjusting, don't. There are other ways to regulate your aquariums water quality, all of which will take care if whatever your concerns may be.

...

I did try to keep this as simple as possible, as it can go into excruciating detail. Unless you're highly interested (if so ask), I would rather suggest you read up on kH and gH rather... Much more pertinent to the aquarium.

Thank you, I had no idea what she was talking about. Your rudimentary explanation was appreciated.

 

[Jennywren]

Okay, chemical science and botanist here. Brace yourself. .... .... ...

I'm gonna need to read that through a couple more times before I get a proper handle on it (even though it's the "rudimentary" version), thank you so much for sharing your expertise!

 

[Jennywren]

Reduction potential, or a reducing compound is able to donate one or more electrons, while a oxidizing compound receives one or more electrons.

So...does a high redox potential describe a situation where there are a lot of ions that want to bond and release electrons as opposed to a situation where all the compounds are stable and inert?

 

[iZaO Jnr]

So...does a high redox potential describe a situation where there are a lot of ions that want to bond and release electrons as opposed to a situation where all the compounds are stable and inert?

Yes a high potential does describe that.

However it does not necessarily mean that it isn't stable. The keyword here is potential... It's not an acting force, just something that had the potential to.