Introduction to Aquaponics

Introduction to Aquaponics

grow beds
Gravel aquapoincs

Aquaponics is the re-creation of a natural ecosystem with the focus of manipulating the Nitrogen cycle to work for your growing needs. It is the combination of Aquaculture (the growing of fish) and Hydroponics (the growing of plants in a soil-less media). The three most important organisms in an aquaponic system are the fish, nitrifying bacteria and the plants. Fish produce Nitrogen in the form of Ammonia both from breathing through their gills and through their waste. When in a closed tank system, if the Ammonia level becomes too high it can cause harm and death to the fish. As the waste filled water is removed from the fish tank it must be accessed by two kinds of nitrifying bacteria in order to convert the Ammonia into Nitrite then into Nitrate. Nitrate is the form of Nitrogen is readily accessible to plants and plays an important role in healthy growth. The bacteria in system must have a large enough surface to live on where the dirty fish water can pass through in order for all of the Ammonia to be changed into Nitrate. The Nitrate filled water then must make contact with the plant roots in the system so that the plant can uptake the Nitrogen and use it for growth. After the water has passed through the plant roots it should be completely free of all forms of Nitrogen and therefore is clean and may be recycled back into the fish tank. In an efficiently running aquaponic system up to 90% less water is used than conventional growing systems.

There are two types of aquaponic growing systems here at Tiano Farm, Media Beds and Floating Rafts. Our Media Beds are made from an IBC tank cut in half, one being filled with water and fish and the other with rock media, bacteria worms and plants. Plants grow directly into the rock media that is constantly flooded and drained with water from the fish. The worms live in the rocks and break down the solid fish waste into a form of nutrients the plants can use. The bacteria also live on the rocks and change the Ammonia to Nitrates for the plants. The plants then clean the water of nutrients and it is recycled back into the fish tanks.

 

Here are pictures of one of our Media Bed Systems:

Aquapoinc Tilapia
Tilapia living in our aquapoinc system

The Floating Raft system is a different form of growing where the plant roots are grown directly into the fish fertilized water. The plants are placed in Styrofoam that float on top of the water and the roots hang into the water to clean it for the fish. In this type of growing system because there are no rocks present, the solids must be removed from the system because there are no worms to break them down. Also, there is no surface area for the bacteria to be grown on so there must be another home for them called a bio filter present. We use plastic balls and mesh for them to live on in our system. The solid and bio filters must be separate from the fish tanks and plant beds.  The ammonia filled water leaving the fish tank must first go through the solids filter, then the bio filter, into the plant beds for the plants to use the nutrients and clean the water to be recycled back into the fish.

 

Here is a picture of one of our floating raft beds:

Float rafts
Float raft Aquapoincs

Daily Update: Tilapia breeding and feed

Tilapia Fish waste solids from the filtration system

What is happening to the Tilapia waste solids from the water filtration system in the commercial production aquapoincs system?

The solids are being used to fertilize the nearby tropical fruit trees.

Previously the Tilapia fish waste solids were meant to be going into the duckweed grow bed system, which provides part of the feed for the Tilapia .

The duckweed system is not at full production yet, and we figured it is in lack of nutrients, so we have been adding Chicken waste as a nitrogen source, and Duckweed likes the ammonia.

Solution: We need to talk to the team to figure out why where they have to be going.

Tilapia breeding room

What is the correct temperature for the Tilapia breeding system or the hatchery?

The water for a Tilapia breeding system should be at 25 C for ideal mating conditions. Right now we are at 22 C and the fish are not mating, there are no eggs, and there does not seem to be any mating circles. Previously we figured the temperature was too high as we were up to 29 or 30 C at some times during the summer months. Juan seems to remember that the fish were reproducing at 28 or 27. That might be the upper range for heat. We bought an aquarium chiller for the summer when the temp goes that high.

Perhaps we should start tracking the fish – how many mating sets are pregnant, name each mating set, organize it to get more efficiency of out of the hatchery.

Solution – We are planning on connecting one of the grow beds from the nursery to the Tilapia breeding take system. It should have the additional benefit of helping to clean the water. We were thinking that the nitrates were too high previously with Nico.

We are not too concerned with cross contamination because the systems are already shared – one way is from the fry Tilapia leaving the breeding room when they become fingerlings.

Black soldier fly larvae harvest

Today we had one ounce of Black soldier fly larvae from the original larvae harvester.  If you remember, Nico started the harvester with chicken waste solids and compost.  It’s now producing about two ounces a week.  There is lots of room for improvement.  I’ll write a blog post about the entire system, from Nico to where we are right now