This document provides instructions for building small to large scale aquaponics systems. It discusses:
- The history and development of aquaponics systems from early attempts in the 1970s-80s that struggled with low nutrient levels, to more successful systems developed in the 1990s at University of the Virgin Islands.
- Details on constructing simple and inexpensive grow beds out of wood and plastic for aquaponics systems, including attaching liners and setting up raceways of connected beds.
- Different methods for growing plants, including using floating rafts or placing plants in gravel beds flooded with nutrient-rich water from the aquaculture tanks.
An Overview of Aquaponic Systems: Hydroponic
Components
D. Allen Pattillo
Iowa State University, pattillo@iastate.edu
http://lib.dr.iastate.edu/ncrac_techbulletins/19/
Aquaponics DIY Manual UN FAO - Survival Gardenersurvivalgardener
What happens when you mix fish farming with hydroponics? Aquaponics! If you’re new to the subject, this type of food production can be an amazing resource. I think of it a bit like hacking nature. Aquaponics takes all of the primary needs of a plant and animal ecosystem and compresses them in to one cyclic package. It’s basically poo powered hydroponic gardening with the extra benefit of having tasty fish to eat. This is the official United Nation guide for aquaponics. All of the concerns with starting and running an aquaponics systems are address in this manual.
For more info on aquaponics and to see our system, you can check out http://survivalgardener.com
An Overview of Aquaponic Systems: Hydroponic
Components
D. Allen Pattillo
Iowa State University, pattillo@iastate.edu
http://lib.dr.iastate.edu/ncrac_techbulletins/19/
Aquaponics DIY Manual UN FAO - Survival Gardenersurvivalgardener
What happens when you mix fish farming with hydroponics? Aquaponics! If you’re new to the subject, this type of food production can be an amazing resource. I think of it a bit like hacking nature. Aquaponics takes all of the primary needs of a plant and animal ecosystem and compresses them in to one cyclic package. It’s basically poo powered hydroponic gardening with the extra benefit of having tasty fish to eat. This is the official United Nation guide for aquaponics. All of the concerns with starting and running an aquaponics systems are address in this manual.
For more info on aquaponics and to see our system, you can check out http://survivalgardener.com
Techxellance agro farm - End-to-end services in Hydroponics and AquaponicsTechxellance Solutions
Techxellance Solutions Pvt. Ltd formed in year 2012 by a group of young and dynamic experts, having more than 18 years of experience in their profession, have come together with a vision of helping society to stay healthy by having healthy vegetables. In a very short spam of time Techxellance team has spread their wings by providing cost effective & innovative end-to-end solutions which helps customers & farmers to cultivate pesticide free & dirt free vegetables at home, terrace or on a farm. Techxellance is into business of sales & service in various technologies like IT & Agro; here in Agrotech division we offer end-to-end solutions to farmers and consumers through Alternative Farming Technology called Soilless Farming with the help of Hydroponics and Aquaponics technology. Techxellance’s team is keenly working on cost effective and accessible solution in aquaponics & hydroponics, garden automation, building facilities & products that respect the natural environment, while simultaneously growing fresher, healthier produce.
Thanking you,
Regards,
Sameer Pokle
www.techxellanceagrofarm.com
Aquaponics is a farming technology that combines the advantages of intensive aquaculture and hydroponics in a recirculating aquaculture system. This depends on WATER. No soil is used.
The integration of fish and vegetables creates an ideal growing environment that is more productive than conventional methods. Consequently, aquaponics is gaining more importance now a day because crop production systems are being forced towards increasing irregularities as drought, floods, storms, cyclones and diseases visit regularly. A simple aquaponic system was designed with the locally available materials.13 pants of 5 different species were grown in an area of 0.27 m2 ( Rashmi M et. al 2013). Three different methods were tested to determine the best system to grow Taro vegetable. The applied methods were T1 = aquaponics system for soilless vegetable culture in gravel bed with fish tank waste water, T2= hydroponics for soilless vegetable culture in gravel bed with tap water and T3= vegetable culture in soil media with tap water as control. Double recirculating aquaponic system (DRAPS) consisting of two independent recirculating units – a recirculating aquaculture unit for fish production and a closed hydroponic cycle for plant production which were connected unidirectional was developed (Suhl J et al 2016). Results revealed that aquaponic system offers better results than other media. This system can enhance the organic farming which could be environmental friendly. Double recirculating aquaponic system (DRAPS) with two independent cycles provides the opportunity to produce equal tomato yields compared to those obtained by conventionally used hydroponic systems. By Using DRAPS fertilizer use efficiency was also improved by 23.6%.
Aquaponic applications for the small farm are becoming all the rage, but how can it truly produce profitably? You need a complete system that supplies it's own feed that is mercury free, soy free, GMO free.
A new way of farming! Grow Fish, Grow Vegetables at the same time, saving water, time, space , efforts and all ORGANIC.
Read this presentation to know more about it.
What makes an effective aquaponics system?PortableFarms
What Makes An Effective Aquaponics System? Brought to you by Phyllis Davis, President of Portable Farms, Inc. and Co-Inventor of Portable Farms Aquaponics System.
Techxellance agro farm - End-to-end services in Hydroponics and AquaponicsTechxellance Solutions
Techxellance Solutions Pvt. Ltd formed in year 2012 by a group of young and dynamic experts, having more than 18 years of experience in their profession, have come together with a vision of helping society to stay healthy by having healthy vegetables. In a very short spam of time Techxellance team has spread their wings by providing cost effective & innovative end-to-end solutions which helps customers & farmers to cultivate pesticide free & dirt free vegetables at home, terrace or on a farm. Techxellance is into business of sales & service in various technologies like IT & Agro; here in Agrotech division we offer end-to-end solutions to farmers and consumers through Alternative Farming Technology called Soilless Farming with the help of Hydroponics and Aquaponics technology. Techxellance’s team is keenly working on cost effective and accessible solution in aquaponics & hydroponics, garden automation, building facilities & products that respect the natural environment, while simultaneously growing fresher, healthier produce.
Thanking you,
Regards,
Sameer Pokle
www.techxellanceagrofarm.com
Aquaponics is a farming technology that combines the advantages of intensive aquaculture and hydroponics in a recirculating aquaculture system. This depends on WATER. No soil is used.
The integration of fish and vegetables creates an ideal growing environment that is more productive than conventional methods. Consequently, aquaponics is gaining more importance now a day because crop production systems are being forced towards increasing irregularities as drought, floods, storms, cyclones and diseases visit regularly. A simple aquaponic system was designed with the locally available materials.13 pants of 5 different species were grown in an area of 0.27 m2 ( Rashmi M et. al 2013). Three different methods were tested to determine the best system to grow Taro vegetable. The applied methods were T1 = aquaponics system for soilless vegetable culture in gravel bed with fish tank waste water, T2= hydroponics for soilless vegetable culture in gravel bed with tap water and T3= vegetable culture in soil media with tap water as control. Double recirculating aquaponic system (DRAPS) consisting of two independent recirculating units – a recirculating aquaculture unit for fish production and a closed hydroponic cycle for plant production which were connected unidirectional was developed (Suhl J et al 2016). Results revealed that aquaponic system offers better results than other media. This system can enhance the organic farming which could be environmental friendly. Double recirculating aquaponic system (DRAPS) with two independent cycles provides the opportunity to produce equal tomato yields compared to those obtained by conventionally used hydroponic systems. By Using DRAPS fertilizer use efficiency was also improved by 23.6%.
Aquaponic applications for the small farm are becoming all the rage, but how can it truly produce profitably? You need a complete system that supplies it's own feed that is mercury free, soy free, GMO free.
A new way of farming! Grow Fish, Grow Vegetables at the same time, saving water, time, space , efforts and all ORGANIC.
Read this presentation to know more about it.
What makes an effective aquaponics system?PortableFarms
What Makes An Effective Aquaponics System? Brought to you by Phyllis Davis, President of Portable Farms, Inc. and Co-Inventor of Portable Farms Aquaponics System.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The Kailash Ecovillage project converting human excreta into organic foodstuf...Kimberly L. King
Since March 2014, a sustainably focused community located on a 0.7 hectares site in Portland, Oregon, USA, has
been undertaking an experimental composting toilet system modeled after the Water Efficiency and Sanitation
Standard (WE-Stand) set out by the International Association of Plumbing and Mechanical Officials (IAPMO).
This system collects urine and hot composts human excreta in a dry-composting toilet system for eventual
use on the community’s organic gardens. The system design reduces the need to access municipal water,
sewer, and electrical infrastructure, enhancing emergency preparedness. It conserves an otherwise wasted
nutrient flow, and safely produces a valuable compost. The system consists of urine collection vessels, multiple
portable collection containers for excreta, toilet paper, and additive, and a compost processor. Urine diversion
has allowed the community to reclaim nitrogen and other nutrients otherwise lost in conventional sewage systems,
resulting in large savings of potable water and significant carbon sequestration via topsoil creation. Logs
showed thermophilic compost temperatures. Compost and urine pathogen testing met American National Standards
Institute and National Sanitation Foundation Standard 41 requirements.
The aquaponics term derives from the words aquaculture and hydroponics, which by definition, has the meaning of aquatics organisms culture and plant breeding techniques without soil, respectively. This activity has how the main feature the sustainability, once the modality looks for the production with low water consumption and high exploitation of waste generated. The present study had as objective to describe the construction of the aquaponics pilot system. This way, based on the literature and acquired experience during the work, a step-by-step method was established for the assembly of the system. To verify the process efficiency, were analyzed the presence of total and thermotolerants coliforms, counting of facultative mesophiles and quantification of micro and macronutrients in leaves and roots of Xanthosoma sagittifolium. There was no presence of total and thermotolerants coliforms in leaves and roots of X. sagittifolium. In the count of facultative mesophiles the roots presented 6x104 CFU/g and the leaves 1.7x102 CFU/g. In the foliar analysis, 1430mg/kg of Fe was observed in the roots. It was concluded that the pilot project was successfully built and testing can be continued with new plants.
Aquaponics Systems for the Production of TomatoesGroup Ka.docxfestockton
Aquaponics Systems
for the
Production of Tomatoes
Group: Kadavu
Members: Michelle Angus, Jane Coneybeer, Chun Chuen Li, Felipe Salvador, Victoria Tycholis
Aquaponics Introduction
Aquaponics: aquaculture and hydroponics combined in a symbiotic relationship for the combined purpose of raising fish and produce with fewer dependencies.
Core Relationship
Excretions from the biological processes of fish provide nutrients for plants
Plants filter toxins out of water for the health of the fish stock
Key Components
Fish tank
Fish species that can live in high density populations (Ex. Tilapia)
Buoyant grow bed with growing medium (i.e. gravel, foam, etc.).
Biofilter containing bacteria (Nitrobacter and Nitrosomonas) for nitrification
Circulation system and plumbing
Monitoring equipment
Advantages over conventional farming
Accelerated plant growth rate
Year-round production
Independent from soil
Highly water efficient
Reduced fertilizer dependency and pollution
Versitile location potential
Crews, Antoine. Figure 5. Worcester Polytechnic Institute, 29 Apr. 2016, web.wpi.edu/Pubs/E-project/Available/E-project-050316-101235/unrestricted/Final_Report.pdf.
Slide 1: Victoria Tycholis
Aquaponics is an agricultural system which combines aquaculture and hydroponics in a symbiotic relationship. The result of this integration is edible fish and fresh produce from a single operation (Palm).
Aquaponics relies on two core ecological relationships. One is between the fish and plants raised. Fish raised in tanks make excretions that enter the system’s re-circulated water. The so-called “waste water” from the fish tank delivers bio-available nutrients directly to the bare roots of the crop plants; this circumvents the soil-root contact normally required to deliver nutrient-laden water. By the absorbing action of crop roots, the plants provide a filtering service to the fish. This allows for clean, habitable water for the fish to continue developing and breeding in.
The second ecological relationship is between bacteria and plants, which enables the first relationship. Bacteria “fix” the nitrogen that plants need by nitrification. The bacteria take the ammonia from fish excrement and convert it into nitrite then nitrate. Two groups of bacteria are required to make the nitrogen in fish excrement available. Nitrosomonas convert the ammonia into nitrite. Nitrobacter then convert the nitrite into nitrate (Nelson). For the farmer, these relationships mean that fertilizer is essentially being produced on-property. The enclosed nature of the entire system means that the farmer doesn’t have to worry about polluting the environment with fertilizer run-off.
The key components of an aquaponics system are as follows: The first component is one or more large fish tanks; the fish that are raised must be able to grow quickly and unencumbered by high population densities, such as tilapia. The second component is buoyant growing beds filled with growing medium such as ...
Biological treatment of domestic wastewater using constructed wetlands is gaining acceptance worldwide
due to low cost and simple operation and maintenance. A treatment system (BIOWATSYST) was
established at Abo-Attwa Experimental Station, Ismailia, Egypt in 1998. The system consists of six
parallel short-deep treatment beds, three sterilization ponds and a disinfection pond. The beds were filled
with gravel and/or sand. Four beds were planted with Phragmites australis and two beds were planted
with Cyprus papyrus. The study evaluates the performance of the treatment beds for the removal of
nutrients and pathogens from primary treated domestic wastewater, with minimizing the length of the
treatment beds. Maximum removal efficiency was 76.3% for the biochemical oxygen demand, 83.9% for
chemical oxygen demand, 59.2% for total suspended solids, 58.6% for organic matter, and 22.1% for the
total nitrogen. Maximum removal efficiency was 82.6% for fecal coliforms, 79.8% for fecal enterococci,
and 87.4% for the coliphages. The results revealed that sand bed was the most effective treatment bed for
the removal of both nutrient and pathogenic bacteria from primary treated domestic wastewater.
Key words: Constructed wetland, Cyprus papyrus, Phragmites australis, physicochemical monitoring,
sewage, wastewater, biological management, treatment beds.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Build and Operate a Simple Small-to-Large Scale Aquaponics System
1. CTSA Publication #161
How to Build and Operate
a Simple Small-to-Large
Scale Aquaponics System
Harry Ako, Ph.D.
College of Tropical Agriculture and Human Resources (CTAHR)
University of Hawaii at Manoa, Honolulu, Hawaii
2. INTRODUCTION
Aquaponics is the symbiotic production of vegetables and fish. Fish eat food and release
metabolites into the water derived from the food. These metabolites are further metabolized by
bacteria, and the products of this metabolism are pumped into a plant grow bed where they are
taken up by plants for nourishment. Aquaponics is suitable for environments with limited land
and water because it produces about three to six times the vegetables (Resh 2004) and uses about
1% of the freshwater used by traditional aquaculture (Rakocy 1989).
Sneed et al. (1975) published the first description of an aquaponic system, which diverted
aquaculture effluent through plant growing troughs. The concept was that the nutrients in
aquaculture effluent could be put to good use to nourish and grow plants; meanwhile, potentially
polluted fish water would be cleaned up before being released into the environment. Plants
showed signs of nutrient deficiencies within a month, likely due to a couple of factors. In
hindsight, fertilizer nitrate nitrogen was 150 times lower than it is today. Furthermore, the
culture water was exposed to sunlight, which allowed microalgae to grow and further reduced
the available nutrients. At around the same time, Dr. John Todd and Nancy Jack Todd led
similar work at the New Alchemy Institute, which resulted in a natural wastewater treatment
system marketed as a ‘living machine.’
In 1978, Lewis et al. sought to address the dilute nutrient issue. They worked with the
first recirculating aquaponic system, which was developed to operate with a high fish stocking
density. While the idea was good, nitrate concentrations were too low at 6–10 mg/L, and
producers were required to add a complete nutrient solution to support tomato growth. As a
general rule of thumb, nitrate levels should be around 46 mg/L. The low nitrate levels coupled
with high amounts of fish feed suggested that massive denitrification, or conversion of fertilizer
nitrate to nitrogen gas, was occurring and the nitrogen was being released into the atmosphere.
In 1986, Zweig developed a simple and productive aquaponic system by matching the
feeding rate and biomass of the fish to the estimated nitrogen needs of the plants. Iron deficiency
was addressed by replacing 20% of the fish feed with rabbit feed. While this work was an
important step in the development of the technology, it went largely unnoticed.
In 1985, Nair et al. (1985) developed a recirculating aquaponics system at the University
of the Virgin Islands (UVI). Similar to the system of Lewis et al. (1978), it used complex
components and engineering that kept operating costs high at $3.18/kg of tilapia produced (1985
prices). Tomato plants grew poorly despite an estimate that nitrogen production by fish should
have exceeded plant requirements by ten fold. Unfortunately, the understanding and prevention
of denitrification was not well understood at the time. Salts that inhibit the growth of some plant
species (Jones 2005) accumulated in the system. Iron averaged 0.1 mg/L, which is less than the
minimum of 1–2 mg/L suggested for hydroponic plant culture (Jones 2005). Researchers Mark
McMurtry, Douglas Nelson, and Paul Nelson of North Carolina State University also developed
a recirculating aquaponics system. They placed their plants in a gravel bed creating an in situ
biofilter.
3. In 1993, Rakocy and Hargreaves reviewed aquaponics research and concluded that
estimates of nutrient uptake and a deeper understanding of culture water nutrient dynamics are a
necessity in the development of criteria for designing aquaponics systems. Rakocy et al. (1993)
attempted to track plant nutrient uptake in the UVI aquaponic systems operated with and without
plants. Unfortunately, nutrients accumulated at equal rates in all systems and uptake by plants
was not demonstrated. A follow up experiment was conducted to determine the optimal fish-
number-to-plant-growing-area ratio. In hindsight, we now believe that the nutrients produced by
fish should have exceeded plant needs in all treatments. Lettuce head weights were about the
same in all treatments irrespective of the range of fish stocking densities tested. The plants
grown in the aquaponics system were smaller than those produced hydroponically (172–248 g;
Kratky 2005), suggesting malnutrition. After refinement, the system produced lettuce heads of a
comparable size (181–344 g; Rakocy et al. 1997). A number of years later, it was demonstrated
that the UVI system could be operated productively and continuously (Rakocy et al. 2004). The
final system consisted of four fish tanks, six plant troughs, a clarifier tank, screen filter tanks,
degassing tanks, a sump tank, a base addition tank, a water pump, two air blowers, and over 200
air stones. A technically trained staff was used to operate it. Rakocy was effectively the first
person to develop a fully-functional aquaponics system and thus, is often referred to as the
‘grandfather of aquaponics.’
Generally, plants were grown in water on floating polystyrene sheets called rafts (Rakocy
1989). Rafts require substantial aeration of the water to provide oxygen to plant roots and to
support nitrification. Kratky (2005) used a system in which plant roots were held out of the water
and exposed to moist air; this could be called a nutrient film technique. Lennard and Leonard
(2006) tested three kinds of systems, some of which have been subsequently used by others.
They tested the following designs: gravel systems flooded with water, systems using the nutrient
film technique in which plant roots were exposed to air and roots were bathed with a thin layer of
fish water, and raft systems. They found that the gravel systems flooded with water were the
best. Ako (2013) tested trickling water under gravel, gravel ebb and flow, rafts with air gaps, and
standard rafts. He found the first two to be best, but the former to be more maintenance free.
It has been more than 20 years since Rakocy modified the technology, yet there are no
known successful commercial systems based on his design. One purpose of the work highlighted
in this publication is to remedy this. However, we can now see in hindsight that aquaponics is
economically challenging. It cannot tolerate low prices for vegetables, low system biological
performance, high capital expenses, or high operational expenses and remain profitable
(Tokunaga et al.) In some Pacific Islands, vegetables are very expensive because they must be
imported by airplane. Aquaponics has the advantage of producing vegetables that taste uniquely
good and are grown organically, as fish and pesticides are incompatible. In particular, our
objectives were to develop systems that require less capital investment and to develop operating
instructions that are based on basic biology and chemistry. Systems should have clear chemical
specifications, and remedies for chemical imbalances should be provided.
4. BUILDING A SYSTEM
The present systems were modeled after Kratky’s (2005) extremely inexpensive
hydroponics systems. Kratky used simple wooden boxes. Grow-bed units are shallow wooden
boxes with a piece of plywood for a bottom (3/4” x 4’ x 8’), two 2” x 4” side pieces (8’ long),
and two 2” x 4’ end pieces (4’ long) (Fig. 1). These grow-beds are quick and inexpensive to
construct (about $84 each). Each bed produces 48 heads of leafy greens, such as lettuce; some
vegetables, such as mustard cabbage (kai choy or Brassica juncea), require 5 weeks to grow to a
pound.
To construct the box, screws are placed through the bottom once every approx. 41 cm (16”).
2x8 stainless steel screws (5.1 cm long and 0.44 cm in diameter) or 3x10 stainless steel screws
(5.1 cm long and 0.52 cm in diameter) are used, as shown in Fig 2. A photo of the bottom and
sides of a tray ready for attachment (Fig. 3.) Boxes are constructed upside down.
Figure 2. Steel screws used to attach
the walls of the grow-beds.
Figure 1. Grow tray
Figure 3. Bottom of tray ready to be
screwed to sides.
5. The plastic liner is then attached (Fig. 4). Growers can find their own plastic; one available
source is www.reefindustries.com.
Figure 4. Attaching liner to the tray.
In practice, many trays are attached to each other. Figure 5 shows a typical setup for commercial
production. Usually 8 pieces of plywood form a raceway. The number 8 is used because rolls of
plastic are usually about 100 feet long. The greatest challenge is to ensure that all of the trays are
level. They need to be level or fish water will puddle somewhere in the tray. Raceways are
supported by double hollow tiles (as seen in Figure 5).
Figure 5. Typical raceways consisting of 8 pieces of
plywood connected end to end.
Trays at the first commercial farm built with the Ako and Baker (2009) system design are about
5 years old and show no signs of wearing. This is because the wood never gets wet.
Tray covers. Plants sit in 2” (5.1 cm) net pots supported by the white polystyrene covers, or
rafts, shown below (Fig. 6). Grow-beds are filled with enough water to reach the bottom of the
net pots, and lettuce plant roots grow down into the water to take up nutrients. It is noted that
this leaves about 5 cm (or 2 inches) of air space between the raft and the surface of the water,
approximating well-aerated tilled soil.
6. Figure 6. Young lettuce plant in a net pot on a
polystyrene sheet.
Recently we have found superior and more consistent performance growing plants in about 5 cm
of volcanic cinder flushed with about 1.5 cm of fish water. We call this a trickle (i.e., trickle
filter) gravel system. Ebb and flow systems using bell siphons are just as good but we prefer
trickle gravel systems because worms can live and eat fecal material from fish in these systems.
The raceway below is an ebb and flow raceway (Fig. 7).
Figure 7. Gravel filled raceway with plants growing
in the gravel.
Water is pumped from the fishtanks into the raceway, and returns to the fish tank via a standpipe
and bulkhead.
As the project evolved, nursery sheets were developed. These are similar to the polystyrene tray
covers, but are drilled much more densely to support the growth of 98 small plants per tray cover
(when the plants are very small). The polystyrene sheets rest on the wall of the tray, and three 4”
7. plastic flower pots may be placed in each tray to prevent sheets from sagging. Most farmers use
seed-starting trays, which are closely-spaced sheets of cups that may be filled with potting soil.
However, potting soil adds organic matter to the system. The seed-starting trays are kept moist
for about three weeks, after which time plants are large enough to plant in growout trays. Most
plants require about three more weeks before they are harvested and sold.
Most farmers automate seeding. Putting one seed in each cup is very tedious and time
consuming. Aquaponics is very labor intensive (Tokunaga et al. 2014) and automation is
welcomed.
Lettuce plants require partial shading to grow well in tropical climates such as Hawaii or the
Pacific Islands (Wolff and Coltman 1990). At UHM, lettuce was found to grow well under 50%
shade cover from a shadecloth. Figure 5 shows raceways with shadecloth.
Initial work has been done with the red sails variety of leaf lettuce. It was found to grow well in
this system. Other varieties of lettuce such as Manoa lettuce or romaine lettuce were also found
to grow well; kai choi and bok choy (Brassica juncea) and basil (Ocimum basilicum) have also
done well. Other farmers grow beets, cucumber, tomatoes, blueberries, strawberries, and
watercress.
Mosquitoes are a frequent problem in raft aquaponics systems, as stagnant water can accumulate
in grow beds. They may be easily controlled by stocking about 3 male guppies in each grow tray
to eat mosquito larvae. Stocking of multiple genders may lead to breeding, and if populations
get too high the guppies will eat the plant roots.
The following ratios work well for aquaponics. We suggest using the nutrient-flux hypothesis,
which matches the feed fed (42 g/day of Silver Cup trout chow with 42% protein) to the amount
of metabolites that must be remediated and detoxified by either a gravel grow bed or a 4.2 gallon
(16 L) submerged biofilter in a 321 L tank (Fig. 8). To make this biofilter, a cylinder measuring
10” by 13” (25 x 32 cm) is made from extruded plastic netting and filled with PVC biofilter
media. A 25 W air pump and three 6-inch airstones are optimal to aerate such a tank. The tank
should be filled with about 200 L of water. The initial stocking density of fish should be 2.5 kg.
The fish tanks must be shaded to prevent microalgae from growing.
Figure 8. Plastic fish tanks with biofilter.
A 15 cm ruler is shown for size reference.
8. Fish feeding should start out slowly and increase over two weeks to the level of about 6.5
tablespoons of feed (42 g) per day. This is a rough estimate, as the fish determine how much
they want to eat. The slow increase should allow for the growth of bacteria, which are recruited
from the environment to detoxify the water. Fish are fed twice daily; once in the mid-morning
when water temperatures begin to rise and once in the evening. The best way to determine
feeding amounts is to feed fish the predetermined amount, and then ten minutes after feeding,
count the number of particles remaining. If 5-10% of the feed remains after 10 minutes, the meal
size should be kept the same; if more than 10% is left over, the meal size should be decreased; if
less than 5% is left over, the meal size should be increased. Iron chelate (1/8 teaspoon) must be
added weekly to each raceway.
Water quality should be tested twice a week so that toxicants such as ammonia and nitrite could
be monitored to ensure they are declining as biofilter bacteria grow. We use a YSI 55 DO meter
to test our water; it is expensive but DO is very important in aquaponics. Dissolved oxygen must
be kept above 5 mg/L in the fish tanks for the fish to feed vigorously, and above 2 mg/L
anywhere in the system to prevent denitrification from occurring. We use a portable pH meter
(Pinpoint; American Marine Inc, Ridgefield, CT, USA) in the field and generally aim to keep the
pH above 6.0. If it falls below, we add potassium carbonate to the water at a level of 1 teaspoon
for every 80 teaspoons of feed fed to remediate pH. We have found that feeding slows or stops if
pH is too low. Total ammonia and nitrite may be measured using inexpensive API or Tetra kits,
though Hach and LaMotte kits are more accurate and should be considered the gold standard.
Total ammonia may be converted to unionized ammonia by using the Henderson-Hasselbach
equation:
pH = pKa + log (unionized ammonia/total ammonia)
pH is measured and pKa is 9.25 for ammonia. Total ammonia or TAN (total ammonia nitrogen)
is measured using the kit. Once the unionized ammonia value is calculated, it must be kept in
mind that 1.46 mg/L is lethal for tilapia (Evans et al. 2006). Nitrite values must be multiplied by
0.31 to get nitrite-nitrogen. A level of about 16 mg/L is lethal for tilapia (Lewis et al. 1986).
Nitrate-nitrogen may be determined using Salifert kits, though Lamotte kits (LaMotte Company,
Chestertown, MD, USA) are more accurate but unstable. Good levels in the fish tank are about
47 mg/L but when the water is flowed, it becomes diluted; we have had successful aquaponics
trials with nitrate-nitrogen at 15 mg/L. Bioremediating bacteria and nutrient levels should
stabilize after about a month. Levels of toxins should be low.
If you experience any issues, use the checklist on the following page to ensure
your system is functioning properly.
9. AQUAPONICS ‘BEST MANAGEMENT PRACTICES’
CHECKLIST
1. Are your plants in the sun? Plants grow by photosynthesis, which requires light
of at least 30,000 Lux. We use a light meter on farms where plants are not in direct
sunlight, and don’t bother with light determinations where plants are in the sun.
2. Are your fish tanks shaded? If not, algae can grow and use up the nutrients.
3. Are your fish feeding to satiety? We normally ask the farmer how much food the
fish eat, and then conduct our 10 min satiety test. In all cases we have found that the
fish were being underfed. This leads to fertilizer nitrate levels that are too low.
4. What is your nitrate nitrogen level? When these are low (<15 mg/L) there is
probably some denitrification occurring; when this occurs, we use the DO meter to
find low DO spots, which must be corrected.
5. Have you considered switching to a trickle gravel system? Our research has
found these are more efficient systems that are easier to maintain.
6. How is your organic certification going? Organically certified vegetables sell
for between $3 and $4 per pound. Prices are the largest determinant of profitability
according to Tokunaga et al (2014).
7. Are your fish dying? If so, unionized ammonia or nitrite may be too high in the
system, and biofiltration needs to be boosted.
10. Literature cited
Ako, H., Research into Technologies of Commercial Aquaponics . Presentation made at a widely sponsored
workshop at Windward Community College, May 25, 2013.
Ako, H. and A. Baker. 2009. Small-scale lettuce production with hydroponics or aquaponics. College of Tropical
Agriculture and Human Resources, Publication No. SA-2. University of Hawaii, Manoa, Hawaii, USA.
Evans, J.J., D. J. Pasnik, G.C. Brill, and P.H. Klesius. 2006. Un-ionized ammonia exposure in Nile Tilapia;
Toxicity, Stress Response, and Susceptibility to Streptococcus agalactiae. North American Journal of
Aquaculture 68:23-33.
Kratky, B. A. 2005. Growing lettuce in non-aerated, non-circulated hydroponic systems. Journal of Vegetable
Science 11:35-42.
Lennard, W.A. and B.V. Leonard, 2006. A comparison
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(gravel
bed,
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Lewis Jr., W.M. and D.P. Morris. 1986. Toxicity of Nitrite to Fish: A review. Transactions of the American
Fisheries Society 115:183-195.
Nair, A., J. E. Rakocy, and J. A. Hargreaves. 1985. Water quality characteristics of a closed recirculating system
for tilapia culture and tomato hydroponics. Pages 223-254 in R. Day and T. L. Richards, editors.
Proceedings of the 2nd
International Conference on Warm Water Aquaculture: Finfish. Brigham Young
University, Laie, Hawaii, USA.
Rakocy, J. E. 1989. Vegetable hydroponics and fish culture - a productive interface. World Aquaculture 20:42-47.
Rakocy, J. E., D. S. Bailey, C. Shultz, and W.M. Cole. 1997. Evaluation of a commercial-scale aquaponic unit for
the production of tilapia and lettuce. Pages 603-613 in K. Fitzsimmons, editor. Tilapia aquaculture:
Proceedings from the 4th
International Symposium on Tilapia in Aquaculture. Northeast Regoinal
Agricultural Engineering Service, Ithaca, New York.
Rakocy, J. E. and J. A. Hargreaves. 1993. Integration of vegetable hydroponics with fish culture: a review. Pages
112-136 in J.K. Wang, editor. Techniques of modern aquaculture. American Society of Agricultural
Engineers, St. Joseph, Missouri, USA.
Rakocy, J. E., J. A. Hargreaves, and D. S. Bailey. 1993. Nutrient accumulation in a recirculating aquaculture
system integrated with hydroponic vegetable production. Pages 148-158 in J. K. Wang, editor. Techniques
of modern aquaculture. American Society of Agricultural Engineers, St. Joseph, Missouri, USA.
Resh, H. M. 2004. Hydroponic food production: A definitive guide for the advanced home gardener and
commercial hydroponic grower, sixth edition. New Concept Press, Inc., Mahwah, New Jersey, USA.
Sneed, K., K. Allen, and J. E. Ellis. 1975. Fish farming and hydroponics. Aquaculture and the Fish Farmer 2:11-
20.
Tokunaga, K., C. Tamaru, H. Ako, and P.S. Leung. 2014. Economics of Commercial Aquaponics in Hawaii. Under
Review at WAS.
Wolff, X. Y. and R. R. Coltman. 1990. Productivity of eight leafy vegetable crops grown under shade in Hawaii.
Journal of the American Society of Horticultural Science 155:182-188.
Zweig, R. D. 1986. An integrated fish culture hydroponic vegetable production system. Aquaculture Magazine
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