Aquaponic Solutions

Backyard

Aquaponics is a great hobby or way to grow your own food in your own backyard. With a small backyard aquaponic system, you can grow enough food to feed your entire family. Many people contact us at Aquaponic Solutions about designing, building and running backyard and hobby scale systems. Therefore, we have decided to dedicate this page to providing information on all these aspects of backyard systems.

System Design

Aquaponic Solutions has advised many people on their backyard aquaponic systems, and the following are some of the main things we have seen people do wrong or completely avoid. Backyard aquaponic systems should encapsulate several design principles to be efficient and effective:

One pump only - for energy efficiency
Gravel bed hydroponic components - easy and efficient plant growth and biofiltration in the one unit
Constant Flow or Ebb & Flow water delivery to the hydroponic component
The preparedness to heat the system water in colder months
The use of the correct gravel type in the hydroponic component
A requirement to test the water on a regular basis

One Pump

There are many plans for backyard aquaponic systems available on the internet. Some are good, some are not. The first thing to remember about an aquaponic system is that it is being used to grow food in a way that confers several environmental advantages. These include low environmental impact and water use efficiency. Many people are interested in aquaponics because of these principles. Therefore, it is often confounding why people then build systems are that are NOT energy efficient! Many of the system designs available from web sites at present are designed using two pumps, which is completely unnecessary and energy inefficient. These systems are based upon designs which are around 10 - 15 years old, and that originate in America. These systems are definitely not ideal and have been superseded by more up to date designs.

Basically, if you locate the outlet from your hydroponic bed slightly higher than your fish tank, then you ALWAYS only require one pump. The water is then pumped from the fish tank, up to the gravel bed, and then returns to the fish tank via gravity flow (which is free and better for the environment!). Simple! Easy! Cheap!

Gravel Bed Hydroponic Component

Gravel beds, whilst not practical on a commercial scale, are the easiest and most efficient hydroponic component you can use for a backyard or hobby system. This is due to several reasons: good plant support, higher plant growth & yield, better water buffering and the fact that the gravel acts as both the biofilter and solids filter. For systems not using gravel beds, more water filtering components are required, therefore raising the cost of the system build.

Constant Flow or Ebb & Flow Water Delivery

Many systems at present advocate Ebb & Flow water delivery to the gravel beds. This is done because of several arguments, these being: it enhances root zone oxygen, it saves energy. These are both valid reasons, however, it doesn't mean that constant flows cannot be used. We tested this in replicated experiments and found that constant flows actually improve water quality (in terms of ammonia levels) and lead to increased plant growth rates and yields. However, it must be understood that constant flows can lower dissolved oxygen at the root zone. Because of this, aeration in the fish tank is usually required, and a simple solids removal device helps because solids in the system will compete for oxygen.

In actuality, you should always remove as many solids as possible from gravel aquaponic systems, as there is plenty of nutrient dissolved in the water. Many people do not understand that about 75% of the fishes waste is in the dissolved form. Solids, if fish:plant ratios are too high (see below), can clog gravel beds and lead to toxic conditions which can kill both fish and plants.

Water Heating

Aquaponic systems work much better if a constant water temperature is used. The main reason for this is the biofilter (gravel bed). The bacterial species that convert ammonia to nitrate have a range of conditions at which they operate at maximum efficiency. In terms of temperature, this is between 20^o C and 30^oC. When water temperatures drop below 18^oC, biofilter efficiency is lost, the bugs "go to sleep", and ammonia spikes can occur. This is why many fish species have a lower feeding rate at lower water temperatures. Therefore, it is always a good idea to try and maintain water temperatures at or above 18^oC in the winter. This may be achieved by many methods, like electrical emersion heaters (like those used for aquariums). However, my favoured method is to use the SUN. It is very easy to rig up simple solar water heaters for aquaponic systems. In addition, using insulation to insulate fish tanks, gravel beds and pipe work all help to retain heat.

Correct Gravel Type

Gravel comes in many shapes and forms, and few people state which gravel is good or bad. For example, I visited a backyard system recently where Red Scoria was used. It was very dusty, very red, and was staining the pipe work. In addition, the Scoria has very sharp edges, which is no good for hands or plant stems. However, the owner could see no problem with this, and was happy to feed the plants and fish to his family. Many gravels may contain toxic chemicals and compounds, like heavy metals. Therefore, choose gravel carefully and correctly!

The best gravel to use is "washed river gravel". Get it at a size of about 10 mm to 20 mm diameter. Gravel that is too small clogs easily and retards water movement. River gravel has nice, well rounded edges that are easy on both hands and plant stems.

Water Testing

Conductivity, pH and temperature (see above) are the 3 main parameters that need to be tested in aquaponic systems.

pH - fish and plants live at an optimal pH. For fish, this around a pH of 6.5 to 8.0. For plants, this around a pH of 4.5 to 6.5. Therefore, aquaponic systems are a compromise between the pH requirements of the fish, and those of the plants. The best pH to run at is around 6.7 to 6.9. This is O.K. for the fish (as it protects against ammonia toxicity), and is O.K. for the plants (as it allows them to uptake the nutrients they require for growth). pH may be tested with simple pH kits obtainable from aquarium stores for less than $20, or by using electronic pH meters.

Conductivity - this is a measure of the amount of dissolved nutrients in the water. The higher the conductivity is, the more nutrients there are. People familiar with hydroponics call this EC. Good plant growth can be achieved at many conductivities. However, for a good amount of nutrient availability an EC of around 2.0 (2,000 microsemens/cm) is acceptable. However, it must be remembered, plants will grow at lower conductivities.


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		Backyard Aquaponics is a great hobby or way to grow your own food in your own backyard. With a small backyard aquaponic system, you can grow enough food to feed your entire family. Many people contact us at Aquaponic Solutions about designing, building and running backyard and hobby scale systems. Therefore, we have decided to dedicate this page to providing information on all these aspects of backyard systems. System Design Aquaponic Solutions has advised many people on their backyard aquaponic systems, and the following are some of the main things we have seen people do wrong or completely avoid. Backyard aquaponic systems should encapsulate several design principles to be efficient and effective: One pump only - for energy efficiency Gravel bed hydroponic components - easy and efficient plant growth and biofiltration in the one unit Constant Flow or Ebb & Flow water delivery to the hydroponic component The preparedness to heat the system water in colder months The use of the correct gravel type in the hydroponic component A requirement to test the water on a regular basis One Pump There are many plans for backyard aquaponic systems available on the internet. Some are good, some are not. The first thing to remember about an aquaponic system is that it is being used to grow food in a way that confers several environmental advantages. These include low environmental impact and water use efficiency. Many people are interested in aquaponics because of these principles. Therefore, it is often confounding why people then build systems are that are NOT energy efficient! Many of the system designs available from web sites at present are designed using two pumps, which is completely unnecessary and energy inefficient. These systems are based upon designs which are around 10 - 15 years old, and that originate in America. These systems are definitely not ideal and have been superseded by more up to date designs. Basically, if you locate the outlet from your hydroponic bed slightly higher than your fish tank, then you ALWAYS only require one pump. The water is then pumped from the fish tank, up to the gravel bed, and then returns to the fish tank via gravity flow (which is free and better for the environment!). Simple! Easy! Cheap! Gravel Bed Hydroponic Component Gravel beds, whilst not practical on a commercial scale, are the easiest and most efficient hydroponic component you can use for a backyard or hobby system. This is due to several reasons: good plant support, higher plant growth & yield, better water buffering and the fact that the gravel acts as both the biofilter and solids filter. For systems not using gravel beds, more water filtering components are required, therefore raising the cost of the system build. Constant Flow or Ebb & Flow Water Delivery Many systems at present advocate Ebb & Flow water delivery to the gravel beds. This is done because of several arguments, these being: it enhances root zone oxygen, it saves energy. These are both valid reasons, however, it doesn't mean that constant flows cannot be used. We tested this in replicated experiments and found that constant flows actually improve water quality (in terms of ammonia levels) and lead to increased plant growth rates and yields. However, it must be understood that constant flows can lower dissolved oxygen at the root zone. Because of this, aeration in the fish tank is usually required, and a simple solids removal device helps because solids in the system will compete for oxygen. In actuality, you should always remove as many solids as possible from gravel aquaponic systems, as there is plenty of nutrient dissolved in the water. Many people do not understand that about 75% of the fishes waste is in the dissolved form. Solids, if fish:plant ratios are too high (see below), can clog gravel beds and lead to toxic conditions which can kill both fish and plants. Water Heating Aquaponic systems work much better if a constant water temperature is used. The main reason for this is the biofilter (gravel bed). The bacterial species that convert ammonia to nitrate have a range of conditions at which they operate at maximum efficiency. In terms of temperature, this is between 20^o C and 30^oC. When water temperatures drop below 18^oC, biofilter efficiency is lost, the bugs "go to sleep", and ammonia spikes can occur. This is why many fish species have a lower feeding rate at lower water temperatures. Therefore, it is always a good idea to try and maintain water temperatures at or above 18^oC in the winter. This may be achieved by many methods, like electrical emersion heaters (like those used for aquariums). However, my favoured method is to use the SUN. It is very easy to rig up simple solar water heaters for aquaponic systems. In addition, using insulation to insulate fish tanks, gravel beds and pipe work all help to retain heat. Correct Gravel Type Gravel comes in many shapes and forms, and few people state which gravel is good or bad. For example, I visited a backyard system recently where Red Scoria was used. It was very dusty, very red, and was staining the pipe work. In addition, the Scoria has very sharp edges, which is no good for hands or plant stems. However, the owner could see no problem with this, and was happy to feed the plants and fish to his family. Many gravels may contain toxic chemicals and compounds, like heavy metals. Therefore, choose gravel carefully and correctly! The best gravel to use is "washed river gravel". Get it at a size of about 10 mm to 20 mm diameter. Gravel that is too small clogs easily and retards water movement. River gravel has nice, well rounded edges that are easy on both hands and plant stems. Water Testing Conductivity, pH and temperature (see above) are the 3 main parameters that need to be tested in aquaponic systems. pH - fish and plants live at an optimal pH. For fish, this around a pH of 6.5 to 8.0. For plants, this around a pH of 4.5 to 6.5. Therefore, aquaponic systems are a compromise between the pH requirements of the fish, and those of the plants. The best pH to run at is around 6.7 to 6.9. This is O.K. for the fish (as it protects against ammonia toxicity), and is O.K. for the plants (as it allows them to uptake the nutrients they require for growth). pH may be tested with simple pH kits obtainable from aquarium stores for less than $20, or by using electronic pH meters. Conductivity - this is a measure of the amount of dissolved nutrients in the water. The higher the conductivity is, the more nutrients there are. People familiar with hydroponics call this EC. Good plant growth can be achieved at many conductivities. However, for a good amount of nutrient availability an EC of around 2.0 (2,000 microsemens/cm) is acceptable. However, it must be remembered, plants will grow at lower conductivities.

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