Are your Koi
getting sick, find out why.
Look at it this
way, all filters work…they do perform a purpose that is sometimes compromised
by the hobbyists or other unforeseen insults that weren’t added into the
equation when setting the filter up. Each filter that we use has its limits and
the hobbyist easily reaches those limits.
Back in the
seventies we did experiments with under gravel filters (AKA: Bog filter in pond
terminology) to see if pulling water through the substrate was better than a
reverse-flow through the substrate. The theory behind the reverse-flow system
by manufactures was; the substrate would stay cleaner and would prevent water
channeling from detritus. As we all know, water takes the path of least
resistance and when the substrate starts clogging oxygen levels in that area lessen
to the point of degradation of the system.
So we experimented with two 55-gal fish
tanks and under gravel filters that were 12”X23” long times two per tank. The
tanks with the reverse-flow systems; each side had 600-GPH going through each
plate. That’s a lot of water going through such a small under gravel plate,
plus the water was pre-filtered before going into that plate. The other tank
had the under gravel filter set up the conventional way using power heads and
lift tubes of 1” Dia. We ran the test for two years and at 3-month intervals we
examined each tanks substrate.
What we found
that no matter what direction the water flowed through the substrate they
carried the same amount of detritus in the substrate whether reverse-flow are
just pulling water from the top of the substrate through the bottom filter
plate. The reason why this would happen eluded the manufacturers or maybe the
manufacturers knew but didn’t care, the reverse-flow filters made a good
selling point. Because the substrate was electrically charge and using physics
the negatively charge substrates would attract the positively charge detritus
no matter what way the water flowed through the under gravel plates.
For hobbyist,
talking about any electrically charge substrates was never mentioned because
they didn’t know. Scientists knew about water being electrically charge along
with substrates that they were using. It wasn’t until the nineties that
electrically charged substrates and water and air topography was even mentioned
being electrically charged. To this day many hobbyists do not understand the
science behind electrically charge substrates and water, or they just don’t
care.
An Anoxic Filter with Water hyacinth, because Koi love to eat the roots of these plants. |
Because of
this, it doesn’t matter which way the water flows through a bog filter; because
if the substrate isn’t aggressively cleaned it will fill with detritus and
block all chemical and biological pathways. Only in extremely fast moving or
high pressure water flows that has the ability to agitated the substrate and
expel any detritus will the substrate stay open to chemical and biological
pathways. As we all know this just is not a feasible alternative moving
thousands of pounds of gravel continuously.
I think from
what I said here does explain why manufactures abandon the under gravel
filter-though they still make them- for moving filters (like spinning wheels),
Nexus filters (churning the filter medium) or wet dry filters instead. More
oxygen and the movement of the filter medium allow the detritus to dislodge
itself from the substrate or filter medium that’s being used at least in theory.
The theory is
that a moving substrate will not let organics stick to it or clog it.
Nevertheless, this wasn’t quite true in all filter designs, and the correct
design is everything.
However, let’s
don’t get mechanical filtration mixed up with biological filtration, they are
two separate entities and are often mixed-up by hobbyists and one can’t tell if
they are trying to mechanically filter or biologically filter with the same
medium. Some organics are too complex and may take as long as a year or two for
complete mineralization like tree leaves for example. Mixing the two into the
same medium is old school and a standalone mechanical filtration always wins
out over combination biological filters when it comes to higher redox. So very
good pre-filters play the part of a mechanical filter then the biological is
last. (ED: Look at Brian Woodcock’s Anoxic Filter build.) If this is not
adhered to then you will have a plethora of bad bacteria where you are trying
to avoid it.
Once again
hobbyist will think that mixing the two is okay because; the detritus will
breakdown into mulm, which is matter leftover after total mineralization has
taken place, it is the simplest form of waste that is inert and will not affect
water quality any longer. But once again this is not accurate, to make matter
or organics into an inert substance takes a lot of oxygen and it must not
compact because now the pore-water and permeability structure of the medium
will change, once it compacts it then will becomes another filter medium for
anaerobic biological activities to start and that means more ammonium ions back
into solution.
Only a controlled environment under
Anoxic conditions will N2 (Denitrogen gas) be made and the use of Facultative anaerobic
bacteria will utilize ammonia and/or nitrates as an electron excerptor. It will
take the oxygen from these ions and use it. If anyone were to say they have a
natural system mimicking Mother Nature then it would be the Anoxic system and
no other. Natural systems make N2 that is 78% of our atmosphere. We would not
be alive today if these facultative anaerobic bacteria did not do their job in
such a specialized environment like natural ponds have. No N2 production then
no natural system.
So for those
that think forcing detritus and organics into a filter medium and it will break
down to its inert substance this will become a two edge sword that will effect
redox of that medium and not knowingly change the oxygen capabilities of that
substrate/medium in question. This is called eutrophication or more precisely
called hypertrophication, when the ponds ecosystem response to the addition of
artificial or natural substances, such as nitrates and phosphates and in the
worst cases more ammonia that plants love and aquatic animals hate.
In natural
system this may take as long as 100 years, but in a closed system like our
ponds using an incorrectly implement bog filter eutrophication may take only
one year or less, there’s nothing natural about that is there? As time goes on
this medium become a ticking time bomb altering pH and other parameters too and
can kill and entire ponds inhabitance or make them sick from Aeromonas Bacteria
that have many species causing disease in Koi. The two most common are Aeromonas
hydrophila and Aeromonas salmonicida and the worst of the two is the Aeromonas
hydrophila that’s the one that most hobbyists should be most concerned about.
When Koi get sick, the fist thing hobbyists look for are parasites and in most
cases they find none but their fish are still dying.
The telltale
signs of poor water quality is; sickness will strike with sores and body
abrasions not healing or ulcerations, because redox begins to drop to levels
unfavorable for aquatic life. If invasive action is not taken immediately to
clear chemical and biological pathways, then the pond will die. In natural
systems when this happen redox can go as low as -400 mV.
However, an
Anoxic system has none of these problems because pathways stay open to
chemical, biological and gaseous mediators and never close. So far some
biocenosis baskets that are over 20–year old now and still doing the job they
were designed for…biological filtering without clogging. There’s no other
filter on earth that can make the same claim, except a natural system that
Mother Nature herself makes.
A newly planted up Biocenosis Basket with Zebra Rush and labeled for identification. |
No comments:
Post a Comment