Not pond related but still informative
information about building an Anoxic filtration for aquariums.
A while ago I posted something on plenums,
that their use in the aquarium is an essential part of the biological filters
stability. The name of the article was: Placing gravel
on the bottom of your aquarium is so 1960ds.
It really doesn’t matter if you are going to
set up a Dutch Planted Aquarium or if you’re going to forgo plants altogether
and use artificial plants. A plenum under the gravel substrate is the only way
to go for optimum biological filtration.
Click on the link below to read about an
experiment conducted by university students and myself, which proves if water
cannot move freely throughout the substrate then anaerobic condition will predominate.
Plenums serve two purposes, one; they can
have an effect on the reduction of Nitrates NO3
by negatively charging the substrate and keeping algae at bay by Dissimulative
Denitrification. Two; they prevent the dreaded anaerobic situation that begins when
oxygen is deprive from aerobic bacteria and favors that of anaerobic bacteria.
This in turn will start what is called Assimilatory Denitrification and only
make more ammonium ions that will go back into solution once again.
Remember, a negatively charged substrate
attracts positive ions like ammonium; these ions facilitate aerobic bacteria
and facultative bacteria. Facultative bacteria has the ability to reduce the
ammonium ion into Nitrates which it will then use its oxygen (Because it has
three molecules of oxygen attached to one molecule of Nitrogen) and turn it
into N2 known as
Dinitrogen. This ability for the substrate to do this is because of the plenum:
Which allows water to flow very slowly in and out of the substrate encompassing
needed oxygenated water but never allowing it to become depleted of such.
Inside the plenum redox always stays in the high
mV values and never allows oxygen to dip below .5 ppm and stay in what is
called an Anoxic State. Anoxic condition only means that oxygen is at 2-.5 ppm
but not void of oxygen altogether. Without the plenum the substrate even with
thriving plant life will turn black from anaerobic bacteria.
There are three ways of bring oxygenated
water into the substrate. One, by moving water through the medium with airlift
tubes or a mechanical power source like a power head. But now you will have
turned your undergravel filter into a mechanical filter too.
Two, through heating cables laid on the
bottom of the aquarium this intern will cause thermal convection. The trouble
with this method is it only works in the colder winter months and not in the
summer months when the ambient air temperature in the home is warmer. Plus, the
cables may malfunction like they have on me and overheat the aquarium.
Three, with a plenum that becomes
eclectically charged inside the plenum itself and then through diffusion of
ions will bring water into the substrate as needed. Plants will not do this
with their root systems alone. This slow diffusion of water, oxygen and
molecule interface will aid in plant root oxygenation and bacteria growth. You
have a better chance of avoiding dead zones and bad microorganisms’ growth populations
turning the substrate black from fermentation.
The undergravel filter I use is from TopFin
at Pet Smart. The box in the photo cost about $10 USD and comes with 14 black
grid panels that are easily fastened together. They also have a larger box with
24 grid panels for larger tanks.
All you have to do is snap the panels
together in the size you need and place on the bottom of the aquarium. Add the
substrate to within ¾-1" on top of the grids, add some Laterite evenly
over the gravel, and then add the rest of your gravel. It couldn’t be any
easier! So why do so many hobbyists forgo this very easy way of bringing
oxygenated water into the substrate? They still keep insisting on placing the
gravel right on top of the glass bottom of the aquarium, now the intersection
of topography is gone…like this is the right way to do it! What is so hard to
understand about this simple process?
The next photos will give you a pictorial
account of how to set up an aquarium with gravel, Laterite on top of the
undergravel grid panels. This will work for freshwater or salt-water aquariums.
In the salt-water aquarium you forgo the Laterite.
Kevin Novak Ph.D.
Anoxicfiltrationsystem.blogspot.com
Supplies needed…
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UG plates are kept away from the front glass
for cosmetic reasons.
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Adding first layer of gravel ¾-1” deep…
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Good old standby…
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Add Laterite evenly over the top of the
gravel…
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Now add remanding gravel on top of the Laterite
and you’re done. Good for aquariums but not so ponds.
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Reprint of article that I posted:
Placing gravel on the bottom of your aquarium is so
1960ds.
Even though this article (below) by me was
written for ponds it also pigeonholes aquariums too. If you place any gravel at
the bottom of an aquarium and think it is okay to do so…think again. Times have
change and science now tells us differently.
Just substitute the word pond
in this articles for aquarium
and it all fits.
Some hobbyists will
even go as far as making their whole pond into a huge biological filter by
placing rocks, gravel, and small stones on the bottom of their ponds. The same
is true for what happens with this way of filtering, as with any other type.
The stones will begin to clog with smut, dead Algae, and detritus. Ammonium
producing anaerobic bacteria will begin to leach ammonia ions upwards out of
the substrate into solution. Algae then will use this as a food source for this
is a nutrient of prime importance or it has to be converted back into nitrates
by the aerobic nitrification bacteria. Nevertheless, as you can see, that the
pond will be plagued with the same problems as submergence filtration systems
have with clogging and producing more ammonia/ammonium.
Now let’s use this
as an example or a good analogy of how the above method of biological
filtration doesn’t work like it’s supposed to. Let us say you wanted to have a
natural pond, and you wanted to cutout a section of X amount of gallons from
biotope in a forest preserve. You then cut out this section in this biotope and
placed a liner underneath it and then had it dropped into a hole in your
backyard. You would think you would have the perfect scenario! Unfortunately,
you would not, because once you put the liner underneath that extracted natural
ecosystem you interfered with the intersection of topography, which ground
water is going constantly into and out of the water body proper at the
interface of the ground and water surface. The liner has cut off the movement
of water through the soil or in this situation the rocks and gravel substrate.
The soil substrate/roots/water interface is of tremendous importance and is now
disrupted by the ponds liner. Natural ponds constantly have water moving in an
out of them on a continuous basis. This is not just from the top to bottom
movement but from horizontal and vertical directions as well.
Unlike our ponds
that are closed recirculating systems, natural ponds are open systems to
topography and are not plagued with the same ammonia/ammonium ion producing
problems. Therefore, with all that we now know, how can one solve this
filtration dilemma?
The quest to solve,
this frustrating problem started me on a systematic investigation that took
over sixteen years of research. Yes, I did R&D on this Anoxic Filtration
system far over 16-years before it was made publicly known. The answer is not
quite as simple as one would think and a great amount of scientific research
was implemented in overcoming many common problems filtration systems are
plague with. Is this the Holy Grail of pond filtration? Maybe not, but it is as
close to it with what is known by science today.
As the old saying
goes: “If you build a better mouse trap people will buy it!” First, biophysical
rules for the Anoxic filtration are different from that of filtration systems
most hobbyists use in their ponds today. In the filtration systems hobbyist
use, the overall efficiency of the filter is in relation to the
filters-incoming foodstuff. Nutrients flux of incoming nitrogen reacts
differently to levels of nitrates in the system that is if microbial mediators
are in equilibrium with each other. If excess should occur, there may be a lack
of balance of useful microbial mediators. This will occur when clogging of the
filter medium is present or when oxygen concentrations are high in bulk
water.
The Anoxic
Filtration filter media having more anoxic and less anaerobic volume area where
more efficient facultative anaerobic bacteria exist will be able to respond
extemporaneously to the nutrients flux more efficiently than conventional
filters do. The fact is that when glucose is randomly added to these
facultative anaerobes they have an Adenosine Triphosphate (ATP) yield of
approximately 34 times that of anaerobic heterotrophs that are present in clogged
filters or gravel bed filters.
Adenosine
Triphosphate s corresponds to the speed and efficiency nutrients can be reduced
to make energy. Organic carbons do not limit these bacteria and mineral
nutrients as heterotrophic bacteria are, which will have a negative impact on
other chemolithotrophic processes. With the Anoxic Filtration System,
biochemical pathways are always open and never clog. The oxic–anoxic interface
microbial processing is the principal processing, controlling electrons flowing
from organic matter to oxygen in molecular diffusion. This filter also has a
diffusion of nutrients through it influenced by electrical charge. The filters
Biocenosis-baskets are negative mV. Moreover, in the pond are many charged
molecules, which most are positive mV.
The more positive
nutrients are naturally attracted to the filter Biocenosis-baskets that are
then used by facultative anaerobes. These bacteria are thirty times more
efficient than bacteria in oxygen free zones, make better use of phosphorus and
only trace amounts of phosphates. Reducing nitrates back into gas elements,
(Dinitrogen [N2] is called Dissimulative Denitrification.
Making up
Biocenosis-baskets for the Anoxic filtration and plants is really quite simple.
The supplies you will need are large planting baskets (11" x 11" x
7" or 14" x 14" x 10"), kitty litter 10 (with no additives
just plain baked processed clay), and Laterite that will be added to the
substrate. Laterite is a highly weathered remnant of volcanic rock (weathering
implies exposure to tropical temperatures, precipitation and forest derived
humic acids over geologic time) but is not a fertilizer and is very rich in
Iron and Manganese (iron is needed for plants to make chlorophyll). Taking an
open cell plant basket and then fill it with Kitty litter make sure you leave a
small impression in the center of the basket but this however is not mandatory
it can be mixed up in the center of each Biocenosis basket, too. Take about one
cup for smaller baskets and one and a half cups for larger baskets of Laterite
and pouring it into the center of the basket then mixing the Kitty litter and
the Laterite in the center of the basket. Now place only one layer of pond
pebbles on top: This is to keep the Kitty litter from floating up after submerging
it into the pond or being blown off during maintenance. Instead of using pond
pebbles, you can substitute a black craft canvas/screen on top and wire-tie it
to the basket.
The Laterite will
help the bacteria grow in its early stages; then once the bacteria become
established it will be less dependent upon the iron in the Laterite for growth.
Yet in the years to come it is still very important to maintain the Laterite
concentration at all times so about every five to seven years you may have to add
more to the Biocenosis baskets without plants and those with plants will be
governed by the plants growth rate. The good thing about the Biocenosis basket
is it will take years before clogging with organic matter (it may take 25 years
or longer). You will use the same procedure for the planted Biocenosis baskets,
but you will not use the black craft canvas on top of this basket only the pond
pebbles with the addition of an aquatic plant of your choosing.
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