Although not a well known process among many aquarists, with much misunderstanding of both sides of the equation by even some advanced aquarium keepers; the implications of Redox for a healthy aquarium are quite far reaching, especially now with peer reviewed research into the correlation of rH, and thus important for any aquarist considering moving from basic aquarium keeping (or pond) to advanced to understand.
Even the average aquarist should consider this water parameter when
all other parameters check out, yet fish continue to be susceptible to
disease. This may be an important parameter to consider as growing
research in human disease resistance, and even plant growth also
continues to show as research progresses.
As research grows, knowing what can affect oxidation and reduction which are both important in their own way can help an aquarium keeper deal better with sick fish or an aquarium that has a sudden build up of organics. Even lighting and quality of light is showing to have an affect on Redox based on tests!
However some in the aquarium keeping community still seem to be in the dark as per this growing documented research.
Redox, also known as Redox Potential, oxidation potential,
& ORP (oxidation reduction potential) describes the ability for the
loss of an electron by a molecule, atom or ion to the gain of an
electron by another molecule, atom or ion.
Without this ability to gain electrons, many minerals cannot be absorbed and properly assimilated, especially in times of stress.
So it is very important to keep a healthy Redox Balance via both sides of the Redox equation;
(a) Normal oxidizers such as proper/optimum dissolved oxygen levels
(b) To counter oxidative stress (often artificially induced in our aquariums); via proper positively charged mineral levels (such as Calcium and Magnesium) and even level 1 or higher UV Sterilization.
Basically we are attempting to provide enough oxidation to provide ample oxygen, allow for biological organic waste breakdown, and not allow too much bacteria in the water column. WHILE AT THE SAME TIME, not add oxidative stress to inhabitants in the aquarium and allow optimum osmoregulation too.
It is also noteworthy that there is a correlation between Redox Potential and pH
The video below shows some of the correlation of pH and Redox:
Fish Health- Quick pH/Redox Demonstration