|
BACKGROUND:
This article is based on studies about the Redox Potential as it corresponds
to humans and all fish and animals. I have found from practical experience
and research that a lot more can be learned from medical studies than from
many anecdotal aquarium articles, this is not to say that this research then
has to be properly applied and a good aquatic article helps here.
I do not believe this is a subject that many aquarists should stress over,
but a lot has been learned about this subject since I first started
researching this in the 1980s. However the more I have studied this subject
the more I feel that ANY serious aquarist should understand this subject as
it has major implications for fish and aquatic health that often go against
commonly held anecdotal aquarium keeping beliefs.
I have also had to change my opinions about this subject based on newer
evidence. One was should you have a positive or reducing Redox. I based my earlier opinion on
a higher Redox of 300 mV based on many studies of ocean waters, but newer human
research and my own tests over the last 10 years have lead me to the opposite
of -200 to -300. There are some ongoing studies up here in Oregon
about BG algae and where a Reducing Redox may help or hinder. All this said,
maintaining a good Reducing Redox (for both saltwater and Freshwater) can be
as simple as good aquatic husbandry: water changes, proper electrolytes and
minor elements in the water, and simple reducers such as Sodium Thiosulfate
and Magnesium.
Put another way, maintaining a proper Redox Potential is a lot like having an
anti-oxidant vitamin in the aquarium water. The Aquarium Redox is also just
one more parameter towards good disease prevention and long term fish health
and growth. Please see this article about Aquarium Disease prevention; “Aquarium Disease Prevention” .
Or to be even more blunt; Bleach and Potassium Permanganate are oxidizers
(Potassium Permanganate is often used for disease treatment an water
clarification is ponds and aquariums), however you would not want your fish living in an
oxidizing environment for long term fish health, rather you would want your
fish in a Reducing environment where free radicals are not damaging the cells
of your fish and causing problems with Osmoregulation. An
oxidizing environment is what you get with a positive Redox.
What got me started researching this was I have noticed and documented
differences with aquariums (I mostly used goldfish for these tests) with UV
sterilizers, added minor elements (such as Wonder Shells) and
electrolytes maintaining a Redox Potential around -300-350 mV, but was not
sure why health, vitality and especially disease resistance were improved.
The goldfish had less incidence of such infestations as anchor worms which UV
sterilizers cannot truly eradicate due to difficulty killing them in the UV
itself and that Anchor Worms do not get readily caught up in the water
column. The Redox Potential explains a lot of the results I was getting.
This pertains to the Redox potential of -300-350 mV that I have found a
properly installed and constructed UV aids in maintaining (assuming proper
dissolved oxygen levels, and proper mineral levels too, such as kH ). A
proper Redox Potential improves the health of humans AND fish. A Redox
Potential in the -200-400 mV range in human studies has been shown to have
the same affect as anti-oxidant preparations such Vitamin C (and many
others). This shows that the health of aquarium fish can be maintained by a
UV Sterilizer not just by the killing of potential disease pathogens, but by
the maintenance of a proper Redox Potential. I have been observing many
aquariums of such "ordinary" fish as goldfish, both with and
without UV Sterilizers (keep in mind that some UVs are useless by design and
installation), and the goldfish with every other factor equal that had a UV
Sterilizer installed, were generally much healthier.
Another interesting aspect of Redox potential is the correlation of a certain
Redox level and the growth of Blue Green Algae (Cyanobacteria) in Aquariums
and lakes. This is an on-going study however Redox does SEEM to play some
role in the aquarium and lake “plague”. For more information about this, I
recommend reading this article:
Blue Green Algae (Cyanobacteria) in
Aquariums; what it is and how to control it. Currently this is
just an opinion though.
I will also note that the aquariums with the proper Redox had the
electrolytes present as tested via GH & KH (salt, SeaChem Buffer, & Wonder Shells are a good
source), and regular water changes which also resulted in lower nitrate
levels (40 ppm or less for FW, 20 ppm or less for SW). I will note that GH is
not always a good indicator of Redox as some procedures an products can make
your GH test higher than desired (such as in Calcium, Magnesium), but it is
in actuality fine as per Redox Reduction
That all said, please read the rest of the article before I over sell any one
on a UV Sterilizer or Wonder Shells. As often good aquatic husbandry is all
that is necessary for a good Redox Reducing environment.
REDOX POTENTIAL BASICS (OXIDATION POTENTIAL):
Redox Potential (oxidation 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
positive Redox Potential many minerals cannot be absorbed and properly
assimilated. So it is very important to keep a proper Redox Potential (-300 to
-350mV) via proper dissolved oxygen levels, UV Sterilization, and proper
electrolyte levels (such as magnesium).
Oxidation describes the loss of an electron by a molecule, atom or ion
Reduction describes the gain of an electron by a molecule, atom or ion
The above is a simplification of the process, and much more needs to be
considered, please read on.
Oxidized Water:
Oxidized water with its Redox potential of +700 to +800 mV is an oxidizing
agent that can withdraw electrons from bacteria and kill them. The oxidized
water can be used to clean hands, sterilize utensils, and treat minor wounds.
Here are a few oxidizers: ozone (O3), hydrogen peroxide (H2O2), chlorine
(Cl2) and chloramines (NH2Cl).
Reduced Water:
Reduced Ionized with a Redox Potential of -250 to -350 mV readily donates its
electrons to unusual oxygen radicals and blocks the interaction of the active
oxygen with normal molecules. Substances which have the ability to counteract
active oxygen by supplying electrons are called scavengers. Reduced water,
therefore, can be called scavenging water. Reduced water inhibits excessive
fermentation by reducing indirectly metabolites.
Here are a few reducers, in other words, elements or
processes that transfer electrons to another substance;
Magnesium, Calcium, Sodium, and the process of Photosynthesis involves both
oxidation and reducing.
As one can see from the graph that elements such as most metals, as well as
essential elements for aquatic life: Calcium and Magnesium are major reducers
however because of this they are also most easily depleted (the elements at
the top and the bottom of the graph are most easily depleted in their oxidation
or reducing properties).
NATURAL REDOX:
Over
geologic time abiogenic (not biological in origin), biogenic (produced by
living organisms) and anthropogenic (processes are those that are derived
from human activities, as opposed to effects or processes that occur in the
natural environment without human influences) deposits were accumulated in
rivers, lakes and seas. Simultaneously there proceeded the self-purification
of natural water on the basis of the chemical reactions of oxidation and
reduction. Living organisms such as fish are adapted not to "perfectly
clean water", such as distillated water, but to ecologically clean water
with definite content of organic and inorganic compounds, micro-admixtures,
ions and even bacteria or saprophyte (any plant that depends on dead plant or
animal tissue for a source of nutrition and metabolic energy, e.g., most
fungi). The range of mentioned components of ecologically clean water is the
integral result of oxidation and reduction self-purification of water.
At the initial stages of this cycle toxic hydrophobic organic compounds
(molecules that are repelled from a mass of water) are oxidized to the
hydrophilic forms (a molecule or portion of a molecule is one that is
typically charge-polarized and capable of hydrogen bonding, enabling it to
dissolve more readily in water than in oil or other hydrophobic solvents),
which are characterized by the better biological compatibility. Energy of
oxidation of degrading organic compounds is absorbed during reduction
chemical transformations. Excess of ions of the heavy elements transforms
into insoluble, inert, nontoxic forms. Concentration of ions of light
elements is stabilized. Just in such water live the water organisms, and land
animals drink such water.
Spring waters, which are considered to be the most clean according to the
ecological criteria, are filtered through the rocks and subjected to the
oxidation and reduction, sorption and catalytic influence. As rule, they are
mineralized and include non-volatile organic substances, which are detected
by the permanganate oxidability (expressed by oxidability by potassium
permanganate and potassium dichromate).
After electrochemical purification water keeps its initial neutral values of
pH, but ORP (Oxidation Reduction Potential) of water shifts toward the
negative (electrode or reduction) values. The resulting purified water
obtains the antioxidant properties with characteristics of pharmacological
activity close to the properties of the antioxidant preparations (a
-tocopherol, b -carotene, vitamin C etc.). In case of dilution of polyvitamin
preparations in electrochemically purified water ORP of mixtures is decreased
approximately by 200 - 400 mV in relation to the control solutions with
non-treated drinking water.
This partially explains how a proper Redox Potential improves the health of
the fish or other aquatic organisms as I have observed. Bringing this back to
my observations of goldfish aquariums; All aquariums with the same filtration
(canister filter with sponge filter), the same feeding schedule and food,
even the same basic goldfish (a mix of ryukins and orandas); The aquariums
with the quality, properly installed UV Sterilizers (again assuming proper
dissolved oxygen levels) not only had less incidence of disease, but general
health, appetite, vigor, growth, and water clarity were all improved.
Here is a Quote about pH vs. Redox:
Traditionally we have judged the properties of water from the standpoint of
pH, in other words whether water is acidic or alkaline. According to Dr.
Yoshiaki Matsuo PhD., the inventor of the Ionized Water unit, "In my
opinion, Redox potential is more important than pH. The importance of pH is
over emphasized. For example, the average pH of blood is 7.4 and acidosis or
alkalosis is defined according to deviation within the range of 7.4 +- 0.005.
But nothing has been discussed about ORP, or oxidation-reduction
potential."
Source: http://www.ionizers.org/water.html
REDOX POTENTIAL AS IT PERTAINS TO AQUARIUMS:
Another way to look at the Redox Potential in aquariums is to the relation of
waste particles and acid production, as well as dissolved oxygen and most
importantly depletion of key important elements. The more waste, the less
Redox Potential due to more nitric acid production and the depletion of key
elements, but this is an over simplification as there is much more to it than
this.
You really need to look at the electrolyte balance in your aquarium. Calcium
as well as Magnesium are both important reducers, however they are both
easily oxidized as well (see the graph in the Redox Potential Basics
section). So for proper reduction, these elements need to be replaced.
As stated earlier, Redox is often 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.
Also as noted in the beginning of this article, this is not a parameter to
stress over, HOWEVER, Redox reduction should NOT be blown off as many
anecdotal/uninformed commentators do in many aquatic forums. The more I have
studied and observed in this subject, the more I feel it should not be
ignored.
Active oxygen molecules, or free radicals, are produced in the water and the
fish’ body. They are extremely reactive and can also attach themselves to
normal, healthy cells and damage them genetically. These active oxygen
radicals steal electrons from normal, healthy biological molecules. This
electron theft by active oxygen oxidizes tissue and can cause disease, these
are proven facts! This why the constant hammering by some uninformed
aquarists against UVs, too high a GH (which is not always a good indicator of
electrolyte balance anyway), and even Wonder Shells is ludicrous. Your GH may
test higher than desired but in actuality is maintaining a healthy Reducing
Redox via Calcium (Facts about Calcium, an
essential reducer), Magnesium, ect.
One final note about the Redox Potential; Before it seems that you must rush
out and buy a UV Sterilizer to maintain your Redox Potential (this is just
one aid that I found to be the easiest and most sure fire, but even UV
Sterilization is not enough if the other parameters for proper Redox are out
of balance). You can maintain your aquarium’s Redox Potential through these
methods:
[1] Proper water changes with ion balanced clean water (electrolytes) with a
GH of at least 100- 200 (GH will supply many important reducers such as
Magnesium) and with a kH of at least 50-100 ppm. A proper Reducing Redox is
another reason for water changes and is also a major reason to not use drinking water drinking
water intended for human consumption unless it is properly re-mineralized.
[2] Good aquarium circulation
[3] Or simply an reasonable supply of dissolved oxygen provides by diffusers
on power heads or internal filter, air stones, spray bars on the returns of
canister filters, ECT. Just make sure you are doing a good job of breaking
the surface tension of the water, as this is where gasses, including oxygen
are exchanged!
[4] Proper Calcium, Magnesium, sodium, and general electrolyte levels, THIS
IS VERY IMPORTANT! (Wonder Shells help here)
I have a good article dealing with kH, Calcium, and Magnesium here:
CALCIUM, KH, AND MAGNESIUM IN
AQUARIUMS; How to maintain a Proper KH, why is calcium important
[5] Also ponds with “flow through” or spring fed water sources will maintain
a good Redox Potential.
[6] The a UV Sterilizer is one more predictable and proven tool here (when
properly installed), but also not a cure all to otherwise poor conditions.
UVs work two ways in my research; [1] they morph oxygen (O2) molecules into
Ozone (O3), the O3 quickly degrades, the UV then [2] transfers electrons to
substances, thus reducing.
As a side note it is the Ozone layer that blocks many harmful UV rays from
reaching the Earth, this is due to the reaction of UVC and Ozone high in our
atmosphere, so by using a UV Sterilizer (which has safely contained UVC
radiation), you break down radicals such as Ozone in your aquarium
For Redox problems, possible problems:
* Driftwood; make sure you soak all Mango Wood or Drift wood for several days
in a solution of 2 tablespoons pure salt to 2-5 gallons of water to leach our
impurities. Even then if you continue to have problems, remove the wood. Over
use of peat can also cause similar problems.
* CO2 generators if not kept at a balance can also cause problems with the
Redox Reduction abilities, this is rare, but worth considering. A good link
to help here is:
Measuring CO2 levels in a Planted
Tank
* An abundance of organic mulm in filters or substrate. Check your cleaning
procedures.
* A lack of electrolytes, as mentioned earlier, Wonder Shells can help
here, BUT they are not a cure all for other problems.
* A tank with high nitrites and nitrates (nitrates are a mild oxidant) will
also tend to be high in nitric acid (but not always); a properly cycled tank
is important!
A simple test of Redox can be performed using Methylene Blue and any
reducer such as powdered Wonder Shell. Simply add about ½ teaspoon powdered
Wonder Shell to 8 oz. of water, stir, then add one drop of Methylene Blue to
the solution and stir. The Methylene Blue will dissipate due to the reducer.
Taking this test a step further into the real world, if you add Methylene
Blue according to standard dosage to your aquarium water (remove the water
for this test), and it stays a brilliant blue, you probably have a positive
Redox. If the color dissipates at all (even the slightest) you probably have
a reducing number. This test in no way replaces the accuracy of Redox meter,
but it is a simple way to get a handle on your aquariums Redox health.
SUMMARY:
Also this is a relatively unexplored are of fish keeping, and there is still
a lot to be learned here and I have to admit having to change my opinions
based on newer evidence.
For further information about WHY YOU SHOULD USE A UV STERILIZER
Credit for some of this information: www.redoxdrink.com/redox_potential_info.htm
Another good article about this subject that I found is this: ORP and the Reef Aquarium
Here is a quote from this article” Many aquarists have been lead to believe
that ORP is a measure of water quality or purity. Manufacturers selling
ozonizers and other oxidizers (like permanganate) have been especially keen
to present that idea. But is it really true? Is a higher Redox indicative of
"purer water" even when that Redox is manipulated artificially by
adding strong oxidizers? Or is such an addition analogous to an air freshener
that masks odors? I don't know the answer, but I think that aquarists and
pond hobbyist should ask the question, and hope to hear useful answers before
adding such materials to their aquaria or ponds.”
This statement is where many aquarists and pond hobbyist have gone wrong in
my opinion, A positive Redox is NOT a measure of water quality, but at least
a Reducing Redox has more potential for a healthy aquarium.
More references:
Redox and Electrochemistry
|
|
|
