Gardening with aquaponics is a passion
for me. For almost 2 years I've visited my fish first thing in
the morning, and it's the last thing I do before bed. I enjoy
the science and systems that sustain this marvelous symbiotic garden
with biological interactions that continue to flourish and amaze
me.
I'll warn you that a lot of what you will find on the
internet is hype and rubbish. For example growing lettuce at
four times the normal yield is just not going to happen. Aquaponics
is not going to feed the world, and it's not as easy as many make it
look, and unless you are a top notch salesman you will not grow rich
selling produce, and fish or aquaponic systems. Beware of people
selling anything related to aquaponics. There are no secrets in
aquaponics.
Why do you want to grow with aquaponics?
Chances are you either want to
1. save money on food,
2. avoid
kneeling,
3. reduce your water consumption,
4. be sure you are
eating healthy organic food,
5. help reduce the depletion of
fossil fuel and lower the carbon foot print of your existence.
Maybe it's all of these, but
"traditional aquaponics" is not a sustainable method. To be
fair, I can't think of any method of farming that provides animal
protein in a sustainable fashion, especially if we are not able to
allow the animal to free roam and forage for their own food. After
you add up all the energy involved with aquaponics it still uses more
energy to pump water than the caloric energy it grows. But aquaponics
is a move in the right direction, and it does save transportation energy. In ideal locations aquaponics could
produce 30,000 lbs of fish per acre per year compared to less than
100 lbs for cattle, but don't forget the fossil fuel required to make
that happen. For more on that [
CLICK
HERE].
As a side note, farming in general tends to be wasteful. 400 gallons of oil is used annually to feed EACH modern human. 34% for manufacture of inorganic fertilizer. 19% for operation of field machinery. 16% for transportation long distance. By growing in our back yards with free nutrient rich sources which I will tell you about later. We can save a lot of oil, but we need to be conscious of our own waste. Pumps, heaters and lights use energy.
This is why I strive to design low energy systems,
and grow with the seasons. These integrated systems qualify as
Permaculture,
and I will show you how to accomplish every one of the goal on that
list! My first rule is don't fight Mother Nature. She can be generous
if you work with her.
Traditional aquaponics may never grow
enough food to get back what you invest, but you will save a lot of
water, know first hand how safe your food is, and if you design it
with raised beds or vertical towers you will not have to get down on
your knees.
Growing a garden is a challenge, at least it was
to me. Aquaponics is not any easier, and often times more difficult
than soil based gardening. I don't consider myself an expert, just
experienced. I hope I can help you get you off to a good start
because it can provide a great deal of enjoyment.
Here is a
list of topics I will cover
Sustainability
Water
Quality
Carbonates, pH, water chemistry and nutrients
Iron
Media
beds
Media
Radial Filters
Cycling & Nitrification
The
System Build
Concrete
Wood Tanks
International Bulk Containers
(IBC)
Drums
Bell
Siphons
Timed Fill and Drain
Old School Fill & Drain
Air Pumps
Airlift Pumps
Electric Pumps
CHOP 1 vs CHOP
2
Level Systems
Flow Rate
Fish
Compassionate Killing of Fish
Fish Food
Breeding Fish
Level Systems
Media Beds
Wicking beds
Earthan Beds
Wicking Pots
Deep
Water Culture (DWC)
NFT (Nutrient Film Technech)
Vertical
Towers
Bioponics
Plants
Green Houses
Rocket Mass Stoves
Evaporative Coolers
Floors
Pipe sizes
Insulation
Lights
Heating
Starting from Seeds
Keep a Log
Sea Salt
Pest
Control
Site & Experts to follow
I want to talk about the many questions
I had as a newbie aquapon, and discuss some brilliant ways to improve
traditional aquaponics.
Questions will always come up when
designing your first system. I will attempt to remember what mine
were, and anticipate what yours are too. I also want to mention an
alternative to aquaponics with fish. Bioponics is aquaponics without
fish. It uses other sources of nitrogen there by avoiding many
problems and expenses involved with raising fish. If you do not eat a
lot of fish I encourage you to go this route.
Water Quality
There are often concerns about detritus in the media and water.
Let me first say, worms in all of your media beds are very beneficial
whether it be
Earthan,
Wicking,
or LECA (Lightweight Expanded Clay Aggregate). They consume dead
roots, uneaten food, and with the help of bacteria in their guts,
make minerals available to the plants through a process called
chelation. They help keep the media clear of excess gunk, and feed
the plants in the process. Worms (Eisenia Foetida – the Red
Wiggler, Californian red worm) to be exact should be in your system.
You can even feed them to your fish.
Carbonates are bad for
beginning systems because they remove a level of control for
beginning systems (i.e. before your nitrification efficiency is up).
Your related acidification is really weak and carbonates can
overwhelm the process, leading to chronically high pH. (i.e. 8+)
which limits nutrient availability and makes it difficult to
stabilize your system where it should be (below 7 for commercial
systems). -
Nate
Storey (Bright Agrotech)
pH and water chemistry and
nutrients:
If the pH gets too high you will need to lower with
acid. Buffing from the carbonates in your grow media, and local
water supply may make the pH difficult to adjust.
 |
| At the point at where the buffer is overcome any further amount of acid will cause a drastic pH change |
GO SLOW. As you add Hydrochloric
acid the pH will drop, and then bounce back. Don't get
frustrated and dump extra in. You will reach a point where it
kicks in and then a little goes a long way. It is possible to kill
your nitrifying bacteria if you go too low.
I've never had a
problem with low pH, but the same applies. Add a threshold
level of HCl (Hydrochloric Acid) or KOH (Potassium Hydroxide) and
then test pH a day later and adjust with a smaller adjustment dose.
This is actually safer than calculating because it allows other
variables to impact pH over the course of 24 hrs.
Some people like to keep pH adjusted water on hand. Rain water can also be used to avoid adding calcium bicarbonate when topping off the system.
A Reverse Osmosis (RO) system removes calcium bicarbonate from the water. They are expensive but they eliminate the constant struggle many find when striving to maintain a perfect pH.
Iron is
almost always lacking in aquaponic systems. The form of iron is
very important. The three common chelated forms (iron-EDDHA,
DTPA and EDTA) differ in their ability to keep iron soluble and
available to plants as the pH increases. Between a pH of 4.0 to 5.5,
any form of iron will work (including iron sulfate) at supplying iron
to the plant. However, as the pH increases above 7.0, only the iron
from Fe-EDDHA will have high solubility. Iron-EDDHA 4 ><
9 Iron-DTPA 4 >< 6.5 Iron-EDTA 4 >< 5.5 Research has
shown that the ranking of iron forms from most effective to least
effective at supplying iron at high media pH is Fe-EDDHA Iron-DTPA >
Iron-EDTA > Iron sulfate. If iron is applied in a form that is not
soluble because of high media pH, then most of the nutrient will not
be available to plants until media pH is lowered.
In general the
best products will say EDDHA (Sequestrene 138) because they work over
the widest range of pH. Sequestrene 330 is ETPA and it is more
affordable. Use Sequestrene 138 only if your media is alkaline and
calcareous If your soil/media is very acidic I would still use ETPA
Sequestrene 330 rather than EDTA. ETPA (Sequestrene 330) is the best
all around iron to buy if your are maintaining your system between
6.2 and 6.5. Iron Sulfate can be used as a foliar application in
aquaponics, and may not be terribly detrimental to your fish, but I
would not use it when there are better choices.
Sequestrene is
what I use and it's widely available on the internet, but others are
good too. Sequestrene 138 may has been reported to turn the water red
but I've only used 330 so I don't know for sure if that is true or
how much of a problem it is.
Media beds clean, and
filter the water, but that is not their
primary purpose. In fact even a bio-ponic system (aquaponic system
without fish) will accumulate muck in the
media. To a certain extent that is what you want for good
nitrification and as your system matures it will continue to improve. What you don't want is food and poo clogging the media,
and creating anaerobic spots. Therefore we remove the detritus from the
water with a
radial filter. The main purpose of media is to provide nitrification,
and as luck would have it, media beds provide a place to grow plants.
People from the aquaculture world often miss this last point and try to
incorporate a very efficient Fluidized Biological Filters as well.
The
primary focus of aquaponics is plant growth and fluidized filters also
known as moving bed filters create no space for plants, but there are
situations where they may be useful. For example you may wish to have
more fish and have no room for more garden beds.
Media provides filtration, a place for
plants and most importantly nitrification.
BSA (Biological Surface Area) depends upon the SSA (Specific Surface Area) of the media. The higher the BSA the better because the bacteria which provides nitrification likes to grow on surfaces. Most IBC systems average about 25
ft2
surface area per pound of fish. 100 or more sq ft per pound would be
really great for the fish, but somewhere in this range is good.
The
surface area of the media where the bacteria grow increases with porous
media. Kaldness is used in aquariums because it has been designed to
provide a very high SSA of about 244
ft2/
ft3, while providing good flow. Flow is the crux, because even though media such as sand has a high SSA of about 270
ft2/
ft3. and a void ratio of about 40% the flow rate is too slow.
There is a wide range of
media with good flow and high SSA, but some to stay away from are any rock that will change the pH
such as marble or lime stone and GrowStones in apquaponic systems because they are made
of glass which will leach into the fish tank and harm your fish. They would be great in a bioponic system though.
The
best products are LECA (Lightweight Expanded Clay Aggregate),
Expanded Shale or Bio-Char if you are able to afford, and obtain them.
For the rest of us Lava Rock is my preference because it is cheap, porous,
not too heavy and contain a lot of minerals for the plants. Microporous solids called zeolites form in volcanic rocks. According to
Russel Water Gardens - Lava Rock has an SSA of 86
ft2/
ft3 and a bed porosity of 20%
For comparison I found this
reference
gravel (40–70 mm,specific surface area of 700 m 2 / m 3 and bed porosity of 0.4)and a LECA with the commercial name of Filtralite NR(4–8 mm, specific surface area of 1250 m 2 / m 3 and bedporosity of 0.45).
I converted that to inches and feet.
1.5-2.5 inch gravel has an SSA of 213
ft2/
ft3 and bed porosity of 40%
1/8–3/8 inch LECA has an SSA of 318
ft2/
ft3 and bed porosity of 45%).
Some of these figures do not seem to jive... It may be that the 2' gravel was not ordinary drain rock.
 |
| Nate Storie showing specifications for Sand, Pea Gravel, 3/4" Rock, 1" River Rock and his Zip Tower Media |
Radial Filters are inexpensive to build, extremely
efficient, and offer the side benefit of capturing fry before they
are eaten. To grow healthy plants we must keep the roots clean, and
the radial filter will do a better job. There are many versions of
radial filters on the internet, but the principal is pretty basic,
and easy to understand. A radial filter will remove most of the
detritus by slowing the water down, and allowing it to settle to the
bottom of the radial filter, thus keeping your DWC raft beds, and
media beds as clean as they need to be.
 |
| Basic radial filter |
There have been quite a few other types
of filters tested, but any attempt to use filter pads will create a
lot of extra work, and jeopardize the clear flow of water if you
forget to clean it. Depending on the size of your filter you will be
married to that chore more often than you like.
I only do
this when my fish have babies, but occasionally I will place a filter
inside my radial filter on the exit pipe in order to save the fry
that get sucked in. I can then move them to a safe tank until they
grow a bit larger.
Cycling
One
of the biggest blunders newbies make is to buy fish before the system
is cycled. Cycling involves growing bacterial (nitrification) which
will naturally find their way into a aquaponic system. There is no need
to buy this bacteria, and every product I have ever used did absolutely
nothing. This includes products claiming to have several bacteria strains, and
those claiming to have special enzymes. Nitrification takes a minimum
of three weeks, and as your system ages this process will mature and get
even better.
There is only one way to speed the process. You can
obtain a fresh bucket of media from an established system and add it to
yours. Water from an established system will not work. To feed and
grow the nitrifying bacteria simply add enough urine to maintain the
ammonia at about 0.5 - 1.00 ppm more or less, and let the water flow
through the media and it will begin to grow.
There is possibly one other way to quickly establish nitrification, but I have never tried this.
Nitrifying bacteria live on surfaces therefore a high BSA is good. Nitrification
is a process where bacteria convert ammonia to nitrite and other
bacteria convert nitrite to nitrate. This is a two-step oxidation process of
ammonium (NH
4+ or ammonia NH
3) to nitrite (NO
2-) then to nitrate (NO
3-)
. During the cycling process do not adjust your pH unless it falls below pH
7. The bacteria prefer a higher pH. The pH can be adjusted later when the bacteria have become
established. It is this nitrification process that removes the ammonia
and nitrites from the water and creates a clean healthy environment for
your fish. Without it you will be doing several water changes per day
of burying dead fish.
Nitrogen is a key component of
aquaponics.
The United States uses about 13 Million Tons of nitrogen
fertilizer a year. It takes liters of fossil fuel to make just 2.2
lbs or 1 Kg of nitrogen, so alternative sources is a big deal and I hope I can convince you to use sources of nitrogen such as urine and weeds which are simply going to waste.
We add protein in the form of fish food and that breaks
down into nitrogen for our plants. For most of us this is all we need
to know, but if you wish to crunch numbers and maximize the use of
nitrogen then I suggest
Commercial System Design – Nitrogen Budget. Paul Van der Wolf explains the entire cycle in depth.
The System Build
Your first system will probably be done
as inexpensively as possible, and you may be temped to try some of
your own ideas. I can tell you from experience that your tanks need
to be sturdy, thin enough to accept a Uniseal or bulkhead, and of a
material that will not rot from constant exposure to water which I
guarantee you will spill plenty.
Concrete may seem like a good choice,
but only if it is sealed. The problem with concrete is that it will
affect the pH and if you continually force the pH down to an
acceptable level the concrete will also weaken and crumble. There are ways
to seal it with pool paint or wax, but it's is probably better the
just avoid it.
Wood Tanks will rot if water accidentally gets
under the liner. I have successfully
[built
wood tanks using fiberglass], but in the end this was more
expensive than a good solid agriculture stock tank which can
generally be picked up for about $1/gallon. Over time the bulkheads tended to loosen - probably due to the contraction and expansion of the wood.
.
 |
| These bunk feeders make good DWC Raft beds and the stock tanks are perfect for fish tanks |
The
advantage to building your own tanks is you get to make them exactly the
size and shape you wish.
International Bulk Containers (IBC) and
plastic drums also make very good tanks, and the size is appropriate
to most backyard systems. But I like a fish tank that I can reach my
hand to the bottom of so you may want to cut your container down just
a little.
Drums are often free, so it is an ideal way to
start. Some people like them well enough to stay with them. I like
the way Justin has built his grow bed using 1/2 drums because there
is no frame below the drums, but I would have added a support leg in
the center or used 2x12. By the way a barrel has a removable lid a
drum has two bungs.
Bell Siphons work while the flow
remains within the parameters they were designed for, and as soon as
something changes they will fail. As much as I enjoy listening to a
bell siphon cycle through it's phases; and even though I'm the guy
who came up with the idea to use a small reservoir at the end of a
breather tube, I will never use another bell siphon on any system I
build. The reservoir helps, but it's a Band-aid fix. Why bother with
a bell siphon when there are better solutions.
Timed Fill and
Drain are a better choice and they conserve energy. Running a 100W
pump 24/7 uses 2.4KW per day 365 days a year. A 15 minutes on 4 hours
off cycle consumes 16 times less power than a continuous run bell
siphon system! I do not believe turning a pump on and off shortens
the life of a pump, but everyone can have an opinion.
Media
beds traditionally use a Bell Siphon, but a Timed Fill and Drain
system will use less energy and run with far fewer problems.
Timed
Fill and Drain systems use a small weep hole which allows the media
beds to drain more slowly than they are filled. A stand pipe allows
any excess water to overflow back into the sump tank until a timer
turns the pump off. The beds are filled several times a day, and when
the pump shuts off, the water weeps out and drains the media bed.
Old School Fill & Drain
I don't know if this siphon valve has a
name or how well it works, but I first saw it in Travis Hughey's
Barrel-Ponic
Manual. It works by pulling a toilet flapper with the weight of a
2 litter bottle. Just giving you all the options.
Air
Pumps
I'm running my air pump to 9 air stones and moving over 1000
gpm with 2 airlifts. I'm using all the air (200 lpm) my Eco Plus 7
compressor can deliver. It runs at 93W wide open and 51W when closed.
The specs say an Eco Plus 7 compressor is rated at 200 lpm 5.1
psi and 280W. I believe the 280W rating refers to the maximum heat
dissipation the motor coils can endure. I've rebuilt Active Aqua air
pumps and I've looked inside this Eco Plus 7 and found the Active
Aqua to have less space within the enclosure. After I could no longer
rebuild my Active Aqua I bought the Eco Plus. My feeling is that Eco
Plus has created a larger cooling area that allows the pump to
operate much cooler and last longer. I could not pick my Active Aqua
70 lpm up with bare hands whereas the Eco Plus 200 lpm is only warm.
I've done a similar test with my
Ametek
Rotron EG DR083 regenerative blower and found that restricting
the outflow increases the Wattage, contrary to the compressor. The
regenerative blower is great for air stones where the depth is
usually pretty shallow. It delivers 521 liters per minute and uses
just 118W, but the compressor's advantage is the ability to deliver
5.1 psi. The regenerative blower has only 0.867 psi. So the
regenerative blower does not work well for airlift pumps but it blows
a hell of a lot of air to air stones!
Air stones are highly recommended
throughout any system and since we are running an air pump why not
utilize it for pumping water too? That's right airlift pumps will
move large quantities of water on less power, and aerate the water
while doing so.
One of the really nice things about airlift
pumps is the way they can pass solids without clogging. They are in
my opinion far more reliable than centrifugal pumps, and a whole lot
less expensive. My airlift can be built for less then $10 and it
delivers over 1000gph.
Electric Pumps - If you purchase an
electric pump there are some considerations. To keep this paper short
(lol) I'll insert a [
Link
Here]
CHOP 1 vs CHOP 2
CHOP (Constant Height One Pump)
Traditional Aquaponics uses either a CHOP 1 or a CHOP 2 design. The
water level in the fish tank is always a constant height and one pump
delivers water to the fish tank which overflows into the media beds
and then back to the sump tank. Chop 2 differs by one pump delivering
water to both the fish tank and the media beds. These each return
water back to the sump tank. The advantage of CHOP 1 is greater flow
through the fish tank. The advantage of CHOP 2 is the ability to
isolate the media beds and the fish tank. These traditional systems
aerate the water by drawing air down through the media each time the
water level fills and drains.
Level
systems do not waste energy lifting water from a sump tank. Instead
the water is simply pushed along through the system, remaining the same
height from one section to the next. The air lift pump, and air stones
provide all the aeration necessary for good healthy roots.
This
of course does leave the roots sitting in water in the media beds, but
so do raft systems. There may be a few plants that don't appreciate
constantly wet roots, but most do fine. Media beds have been included
in every successful aquaponics system since day one, but a new concept
has evolved which integrates wicking beds with aquaponics. It's called Earthan Beds, and I'll tell you more about that later.
Flow Rate -
Kieth
Tatjana recommends twice per hour, but no more.
The
Aquaponic Gardening Community site recommends once per hour. So
if you have a 100 gallon fish tank you should pump 100 to 200 gallons
per hour. These rules of thumb are good enough, but if you are
designing a commercial system then I would refer you to
"Why
Flow Rates are Critical in Aquaculture" written by Paul Van der
Werf.
Fish are such a wide topic. My advice is grow
what you like to eat, or grow what you like to look at, but don't
grow what does not belong in your neck of the woods.
Tilapia in
Maine is going to require heating the system, and take it from
someone who has been there, it gets expensive. Catfish, are a good
all around fish, but even though they can survive, they will stop
growing during the cold days of winter. If you live in Florida or
Hawaii you might like to grow tilapia, but even in Florida the winter
will require some heat.
The nice thing about Tilapia is they grow
pretty quick, they are hardy, and they reproduce well, but catfish
kept in a warm water tank will also fulfill these qualities. If you
live in a very warm climate, go for it. But most of us will be better
off with a local fish that is acclimated to our area. Perch, Blue Gil
and even trout are being raised in cool climates.
Larger
systems are more stable, but start small. A 100 gallon tank with
about 16 lbs of fish and 16 sq ft of garden is a very nice system.
You can expand the grow bed on that system a little, and stock the
fish a little heavier, but for starters it's best to keep a light
fish load.
Breeding Fish - I have found that fish will breed
without my intervention. But some like to identify the males and
females and place one male among several females. Sexing fish is not
easy, but
Robb
Nash has a good method in his link. Once the fry are available it
is a good idea to separate them so they will not be
eaten.
Compassionate
Killing of Fish
Inhumane and totally unacceptable
slaughter methods, that can take a long time for
fish to lose
consciousness and die, should be prohibited urgently. These
include
suffocating fish in air or on ice, bleeding to death
without pre-stunning, and the use of
carbon dioxide for
stunning.
Only slaughter methods that cause an instant death
or render the fish instantly
insensible to pain until dead should
be permitted. These include percussive stunning
techniques whereby
fish are rendered instantly unconscious when carried
out
efficiently.
I use a 1" dowel about 16" long
to club my fish. The easiest way I've found is to hold the fish in
the net so that they don't slide out of your grasp. Wait a moment
until they settle down and make one swift blow to the top of the
head. Death is instantaneous. There is no suffering, no blood, it's
just a good clean kill.
Fish Food can be a major expense if
you don't find a good source. I buy mine at Tractor Supply where I
get 50lbs for $18.00. The important thing is to look for about 32% or
better protein. For your fry you may wish to buy a more expensive
product with higher protein. Some foods will leave a lot of detritus
so you may want to experiment. How much and how often you feed your
fish depends on temperature. They will not eat as much when cold.
Under ideal conditions you might expect to feed your fish about 1.2%
of their body weight. I like to watch them feed and if they leave
food after a few minutes then I cut back just a little until they
don't leave any food. Take note of how much your fish eat to be sure
your feed rate is approximately 1.2% of what you guess they weigh. If
not you may have a problem with water quality.
Wicking
beds have many advantages when growing fruiting plants. Unlike
lettuce, and kale which are not particular; tomatoes, peppers,
squash, melons, and especially root crops prefer to get their roots
down into the media and better yet the complex soil web provided by
real dirt. With wicking beds we get back to mother nature, and let
her, and all the microorganisms do what they have done since the
beginning of time.
 |
| Scarecrow's demonstration wicking bed |
Aquaponic systems
are prone to deficiencies. Iron being the most deficient mineral of
all. By using wicking beds in an aquaponic system the best of both
worlds is found.
Earthan Beds - Paul
Van der Werf presented his design several years ago. I believe it was
May of 2011. His design differed from previous designs when he used 2"
drain rock below the soil so that the water would flow unimpeded through
the bottom of each bed. The water level remains about 2" below the
soil. He uses large pipes and an air pump to move the water. Up til
then 1/2" to 3/4" media was always preferred due to the larger surface
area. Paul determined that all he has to do is increase the volume of
the media beneath the grow beds to compensate for the loss of surface
area. Now that's a win/win idea!
The Earthan Beds use large smooth rock in order to facilitate flow, but the surfaces of the drain rock provide very little BSA. (probably in the order of about 18
ft2/
ft3). With the rule of 1 pound of fish per 25
ft2 of BSA we would need to increase the grow beds to quite a large area. For example just 100 lbs of fish would require 1800
ft3
of BSA or about 11 cubic yards of drain rock. That's a lot of drain
rock, so a standard media bed with something like lava rock should also be added to increase the BSA.
But if you have the room to add additional Earthan Beds I would go that
route, and grow as much as you can.
Paul Van der Werf said while describing his Earthan Beds, "
There
is no great need to “cycle” the system as the soil will contain all the
nitrifying microbes you can handle and will leach into the gravel
substrate where your water flows very quickly" A system might cycle quickly with the help of some good garden dirt. This leads me to believe the BSA is not entirely dependent upon the drain rock even though the water does not flow through the soil.
Wicking Pots is a similar system. It
uses pots placed on a shallow shelf or shallow tray where aquaponic
water flows similar to Deep Water Culture (DWC) bed. The plants sit
no more than about 1" into the water and the water wicks up into
the pots. I first employed this system for cuttings. This has the
advantage of being able to move the pots around as needed, but this
exposes a lot of water surface to light and air. This exposure can
allow algae to grow and water to evaporate but in my grow room I have
never experienced these problems.
 |
| Pots sit in water over fish tank. Fish can nibble at the Water Cress growing freely on the shelf. |
You may wish to incorporate both of
these wicking styles as well as DWC rafts and media beds, but just to
let you know I like wicking and Earthan beds above all else because
very little water is lost through evaporation. They conserve water
which is the goal of any conscientious gardener.
DWC Rafts
allow you to move plants easily. DWC should used in tandem with Media
beds or Earthan in order to guaranty sufficient nitrification. Large
commercial system like DWC Rafts because it allows them to rotate
crops and squeeze the most production out of their green
houses.
Raft systems are often built with rigid foam
insulation panels which float in tanks about 12" deep. I
personally do not like this material or method, and much prefer to
use 3/4" plywood which lays on top of the bed. Net pots are
placed inside holes just as they would be in foam panels.
 |
| This bed is actually a Kratky Hydroponic bed, but it uses the boards as I've described for DWC Rafts. |
The bottom of the net pot is allowed to
touch the water's surface. This provides moisture to the media
in the net pot by way of capillary wicking action. It's important to
avoid openings because light will grow algae and air will dry the
roots. Place the boards tight to each other and keep every hole
filled. The advantage is moist air around the roots, and a
cleaner more stable grow bed that does not use environmentally
awkward materials. Evaporation is minimal due to the top being
closed. The plywood will last for many years, and can be coated with
fish safe epoxy for even longer life.
Giorgio
presented his
GM
Raft System - an integrated aquaponic design in January 2012 and
others have improved the concept. They may have gotten the idea from
Kratky, but as far as I know Giorgio was the first to integrate the
concept with aquaponics.
NFT (Nutrient Film Technech) uses
tubes The roots grow in the nutrient rich flowing through the tubes.
This is generally a way of conserving space by going vertical. The
downside is the water gains or looses a lot of temperature.
Vertical Towers allow easy access and greater density,
but I see no way to incorporate this into a 'Level System.'
Bright
Agrotech is the leader in this field. Their Zip Grow Towers are
well designed and provide a modular approach that facilitates easy
harvesting and transplanting seedling starts. This system will
transfer a lot of water temperature to the surrounding air.
Dr. Nate Storey pictured above has many
very informative videos about gardening with aquaponics.
Bioponics is aquaponics without fish.
There are many advantages.
1. There is no need to purchase fish
food.
2. No detritus from food to clog up the system from humonia
3.
Bioponics allows changes to the water chemistry without worry of
killing fish.
4. You can use pesticides that would harm fish.
5.
You can grow within a wider range of temperature.
6. There is no
need for a fish tank.
7. Less to worry when you leave for a
weekend.
The disadvantage is the system does not produce
animal protein.
Generally
humonia (aged urine) is used
instead of fish. Aging the urine will kill any pathogens, but to be
practical urine is not a likely source of pathogens in the first
place. If humonia grosses you out then you might be interested in
another method. I am testing to see if grass clippings and weeds can be
substituted for humonia. My initial tests indicate that grass
clipping will provide plenty of nitrogen.
David
Epstein at Bioponica.com has been doing some interesting
experiments using only plants to feed fish in aquaponics. I am hoping
to find a way to do the same in Bioponics. I have found that grass clippings and weeds can cause detritus.
Plants -My advice
is to grow plants you like, and costs you the most to buy in the
grocery store. The important thing is to grow with the season. The
short days of winter will not support tomatoes. Green leafy
vegetables do best in Winter. Cilantro might not grow too well in the
summer if you live in a really hot climate. Choose what grows well in
your area.
Green Houses or
Garden Rooms as I like to call them are great, but beware they can get
very hot in the Summer and cold in the Winter. I use mine for early
starts. Keeping the frost off can be quite an expense.
I also built a grow room, separate from the green house.
I
attempted to design my grow room by calculating BTU losses and gains,
but after all the number crunching was done I finally understood that
relating the math to my real world design had become too complicated for
me. I built a highly insulated grow room, and have found the
temperature is be acceptable in the summer even though the outside
temperatures were 105-111 F for several days. All I did was open the
windows. Inside the temperature reached high 90's but the fish loved it
and the plants did not mind.
Winter on the
other hand causes me grief when nighttime temperatures drop to 20F. I
ran a 1200W heater several hours a day and kept the water at 72F and the
room stays at about 60F, but humidity and my electric bill have caused
me stock my tank with catfish. I don't want to do that again. Mold
became a huge problem.
 |
| Outside looking into my grow room. Evaporative cooler was not necessary |
The grow room is inside an uninsulated
metal shop, and the walls and ceiling of the room are insulated with
R19. The tanks are also insulated with R11. The problem with this
grow room is humidity in the winter and not enough glazing. The room
measures 10’x10’ with an 8' ceiling. The single pane glass faces
south and measures 10 feet long by 40" tall. If I were to do it
again I would add some glazing above the grow bed. East and West
windows are probably not so important because the angle of the sun is
so low.
To fasten fabric or plastic film you can use PVC as
shown in
[this
video]
Rocket Mass Stoves are used to heat garden houses. They
are affordable compared to running a gas heater, but require a little
more attention.
Evaporative Coolers are often used in green houses, they do
a really good job if you live where the humidity is low, but running
a fan to cool the green house is once again wasting energy. Our
summers often hover near 100F or above. I've found that all I need to
do is open the garden room up and let the air blow through. This also
allows bees and other insects to pollinate your plants.
While on the topic of green houses and
living with Mother Nature, I have a few more things to say about
energy. Growing with lights is not economically feasible. Possibly,
if you were to use LEDs, but how does anyone justify the initial cost
of that type of system for vegetables. Grow with the seasons. Leafy
greens in the winter, tomatoes and peppers in the summer, and forget
the high tech crap.
Floors - I promise, you will spill large
amounts of water. Any floor under or near an aquaponic system should
be able to handle being wet. Wood does not fit that
description.
Pipe sizes are important. Once a hole has been
bored into a tank it is very difficult to change the size. 2"
pipes are minimal. The flow of water is impeded by small pipes, and
each turn also adds resistance. It's very important to build your
system with adequately sized pipe the first time in order to avoid
problems with water flow.
 |
| Gunk clogs pipes and makes them run slower over time. This is one reason for large pipes and why bell siphons fail. |
Insulation and building below grade can
help maintain water temperatures. You will have to decide if your
climate demands this extra effort. My experience shows that it does
help but since there ia a lot of surface exposure it merely servers
to soften the swings rather than hold a temperature. If you choose to
disregard my previous advice and plan to heat the water then I would
definitely go to the extra trouble of insulating.
Lights can
be used to extend the grow season. I'm not advocating grow lights to
grow plants to maturity, but only to add a couple extra hours in late
winter to get your starts going early. If you should choose to do
this, do not use any type of florescent or CFL lighting. They are far
too expensive because they have a short 1/2 life, and the mercury is
very toxic if a bulb should break into your system. My favorite is
Ceramic
Metal Halide. They have the best spectrum and the heat does not
go to waste in the cold days of late winter, which puts them on par
with expensive LED lights. Ceramic Metal Halide is being discontinued
even though the replacement may not be as good. But I bought a few
extra and will make them available if the supply runs out.
Heating is a waste of energy, but occasionally
using a heater to get through a short cold spell might make sense.
Building a heater from a water heater element is quite easy, but I
would caution you to use an Incoloy type water heater element
(
120-1500-ELD.
You can purchase them online here at
http://www.plumbingsupply.com/elements.html
Heat pads are also a smart way to keep
your seedling at the right temperature. These small pads have a
built it thermostat to keep a tray exactly at the right
temperature.
Solar is an option I have not used. It might be a
good solution for you.
Starting from Seeds is the least
expensive way to grow. Buying plants from a nursery can expose your
system to unwanted pathogens, disease, and bugs, but this is a rather
small risk in my opinion. Commercial nurseries are very careful now
days to use sterile media and deliver healthy plants. The advantage
to buying your starts is grow bed space and labor. Starting from seed
requires using part of you grow beds for plants that will take time
to mature. Buying a plant from the nursery allows you to make better
use of your space. But if you are like me you will prefer to buy
seeds of particular heirloom plants and save the expense. I start my
seeds directly in the bed where they will grow as well as in trays.
Transplant shock is rarely an issue in aquaponics. I like to place a
bit of Azomite and Insect Frase in the media when I plant a seed to
give it a good immune systems, and all the nutrients it will need
when it grows up.
Keep a Log. Especially for the first year or
two you should keep a log of when you plant, and all of your water
tests which should be done everyday until your system completely
stable and you get to know it so well that you can immediately tell
if something is off. Use your nose and eyes and ears. You may have a
dead fish, or one of your pipes may be getting clogged. If you become
acutely aware you can save yourself a lot of grief by detecting these
things early. If you become a professional grower you will want to
keep a detailed log to protect your livelihood.
Sea Salt cures
a lot of fish problems, and is the least harmful treatment. More fish
die from people trying to treat their fish. Salt is not good with
catfish and can be hard on some plants like strawberry, so you may
have to experiment.
Black
Soldier Flies are an optional food, and many choose to build a
small bin to raise them. I have not had a great deal of success
raising them. It is something I would advise looking into for a very
good source of free protein.
Midge Flys are a gift that may find
their way into your system. The small red or tan worms hide in the
media, and the bottom of the fish tanks and are very good food for
your fish. The Midge Fly looks almost the same as a mosquito, but
Midge Flys have no stringer. I guess that's what you would call the
part mosquitoes stick you with. Anyhow they are easy to confuse, but
midge and their larvae are excellent fish food and they cause you no
harm.
For more information on live food download
[this PDF].
Other foods such as
duckweed,
and
Moringa
tree leaves can be grown for both you, and your fish. It's good
for your fish to have several sources, and since living plants will
not decay you can be sure your fish will have something to eat if you
are not feeding them enough. It is nearly impossible to grow enough
duckweed in their tank. They will eat it faster than it grows so you
will have to grow it elsewhere. I let water cress grow along the
edge. It gives them something to nibble on.
 |
|
Pest Control can be an especially
difficult problem with aquaponics because you must avoid killing your
fish. This is one the benefits of Wicking Beds and Earthan Beds.
Pesticides are not likely to fall into the fish tank or radial
filter. Fish tanks can be located away from the grow beds in a shed.
Vertical towers are also far less susceptible.
I hope you will be
very conscious of what types of pesticides you use. Many will kill
bees which are becoming endangered due to bee-poisoning
neonicotinoids. Rather than get into a pests control hear I will LINK
you to a few posts I made awhile back.
In the beginning I asked what your
goals were. My goals may not be your goals and your resources will
differ from mine, so our systems will differ. As I see it, Wicking
Pots or Earthan Beds offer the best of both aquaponics and soil based
gardening. Consistent moist soil, with benefits of a complete soil
web and low water use. The integrated raised beds, fish production,
and easy to care for gardens will be free of harmful chemicals. The
use of airlifts reduces the power demands, and in the long run
reduces your food costs. Bioponics is another interesting way to go.
I also plan to install some of Nate's vertical towers. He and his team at
Bright Agrotech have done a lot of research, and share more good information about how to succeed with aquaponics than anyone else I know of.
Bright Agrotech's Co-Founder, Nate Storey holds a Ph.D from the University of Wyoming. Doctor of Philosophy (Ph.D.), Agronomy and Crop Science. Nate knows what he's talking about. There is also a link to his Youtube channel below. Nate has documented outstanding results using his proprietary towers.
Many are the considerations. You will probably ponder many
sites and videos looking for ideas before you settle on one design,
but I hope you will consider what I've said. If your system is not
working the way you would like, take another look at this document,
the
[Rules
of Thumb] on the Aquaponic Gardening Community site, and
Kieth
Tatjana's Optimization of Backyard Aquaponic Food Production System
for answers.
Bob Campbell
PS: Along the way I've found many good sites. Here's a few I recommend in no particular order.
WaterRight Australia
ScareCrow's Garden
Rob Bob
Grow Your Greens
Wood Burning Stoves - Permies
Some of the experts I like are
RobTorcellini
Vlad Jovanovic
Paul Van der Werf
Jon Parr
TCLynx
Nate Storey
Rob Nash
PaulHolowko
Tetsuzan Benny Ron
