Redox Reactions: Oxidation and Reduction

Free radical chemistry is the underpinning of 2 broad classes of signaling molecules in biological systems: ROS, which are reactive intermediates of oxygen metabolism, and a closely related group of RNS.
The forms of ROS that are relevant in biological systems include the superoxide radical (O2•–), hydrogen peroxide (H2O2), and hydroxyl radical (OH•).
RNS of biological importance include NO, low- and high-molecular-weight S-nitrosothiols, and peroxynitrite (ONOO–).

An increase in oxidation number corresponds to oxidation, and a decrease to reduction.

Energy of oxidation by way of degrading organic compounds is absorbed during reduction chemical transformations. Excess ions of the heavy elements transform into insoluble, inert, nontoxic forms. The concentration of ions of light elements are then stabilized.
Water organisms, live in such water, and land animals drink it.

Redox Reactions in Photosynthesis

By assigning oxidation numbers, we can pick out the oxidation and reductionhalves of the reaction.

Chapter 22 ("Electron Transport and Oxidative Phosphorylation") in Voet & Voet (3rd Edition) is one of the most important chapters in the entire text (at least in my opinion) and it would help to reread it as you look at the light reaction of photosynthesis in more detail over the next two lectures.

Photosynthesis involves oxidation and reduction by oxidizing ..

This is achieved by a
combination of hardwired genetic pre-programing and adaptive response to environmental signals that the plant and
its cell sense and react to in an 'intelligent' manner.

Applications of Redox Reactions | Chemistry Assignment

Effect on plants:
In a controlled test conducted with terrestrial plants; plants treated with magnetized water (basically Redox Balanced Water) reacted in a test, with a growth in the order of 20% to 40% bigger than the plants treated with regular water.
While no test has been conducted with planted aquariums, it is not rocket science to draw conclusions from this study and apply this to a planted freshwater aquarium and the effect of Redox Balance on plant growth!

Home → Applications of Redox Reactions

As stated earlier, Redox can be more important than pH, there are definitely correlations to pH and the Redox effect on pH.
But you cannot make the assumption that if you have a pH of 8.0, that you have good reduction. Just like with GH, where your GH is high, you can still have low pH.
The bottom line is that there are relations between Redox, GH, pH, and even kH, but these are still individual water parameters.

How to Balance Redox Reactions (with Pictures) - wikiHow

The Redox Potential is always going to be in flux and as yet no scientific equilibrium has been established here.
Maintaining reducers such as Calcium and Magnesium in your aquarium is just as important as proper levels of dissolved oxygen (which raises Redox).
There is evidence both anecdotal and controlled that proper levels of calcium and other anti-oxidants such as Vitamin C (along with other healthy water parameters) will prevent and even cure Hole in the Head disease (HITH). Redox is an important parameter here.
Further Reference:

Redox Reactions: Oxidation and Reduction - dummies

This again is where many will claim that their calcium or other minerals are high enough or even too high (as many still get INCORRECTLY stressed about the high GH brought on by Wonder Shells, totally missing that these mineral blocks are constantly reducing the water via their donation of electrons!).
This is also where water changes and UV Sterilization also help as these processes constantly balance out Redox.
Since water changes (which also aid in oxidation, which is the other side of the equation) can only be done in intervals.
Unless you have a flow through system, the use of mineral blocks, or other water conditioners as well as UV Sterilization to keep a more steady flow of electrolyte donation is important.