Difference Between Hydroponics and Aquaponics Part 4

Thanks for visiting our Part 4 conclusion of Aquaponics systems. We’ll go over vertical towers, Flood & Drain, and CHOP systems. All of these have their own particular benefits…. it’s just a matter of you deciding wish one works best for your needs. 

3. Aquaponics Tower (Vertical Growing)

strawberry towers aquaponics systems

Vertical towers in aquaponics systems are a solution for growers that have a limited area to build a garden in places such as apartment balconies, small townhouse backyards, and indoor layouts, etc. This kind of system design can grow ten times the amount of plants per square foot than conventional gardens.

Aquaponics tower setups were originally used in Hydroponics systems, but have since been modified into aquaponic farming by adding the component of tanks populated with fish.

These “tower” gardens are essentially a grow system of stacked plants growing in net cups inserted up and down a vertical pipe channel. A submersible pump sitting on the floor of a reservoir container below, pumps water with nutrient solution up to the top opening of the towers’ channel. From there, the water trickles down the channel pipe bathing the plant roots as it descends to the bottom outlet of the pipe/channel. Since this is a thin film of water, there is plenty of air in the channel to provide the plant roots with needed oxygen.

Indoor Aquaponics Using Garden Towers

If your vertical aquaponic system is indoors, then you will need some lighting, and a timer to turn them on and off. You can find grow lights online with many watts to choose from. You’ll have to decide which lights to use based on plant types since they have different light requirements. If a plant doesn’t receive enough light they tend to spread unevenly across the growing surface and become spindly in appearance.

If your tower garden is outside you won’t have to worry about using lights for the plants. However, it will limit the number of months that you can grow vegetables. This will be dependent on the weather conditions you live in.

Indoor aquaponics lighting

If plants don’t get enough light, they tend to extend themselves to the point of becoming gangling and top heavy. Energy needed for the fruit and flowers wind up primarily in the stem. I the plant gets too much light they may get burned or become pale.

Red and blue light is what plants need for photosynthesis while yellow lighting is ineffective. Incandescent lights will put out a broad range of lighting but their high heat level may damage young tender. Fluorescent tubes work well for plants but LED Grow lights are better and last 10 times longer. The important thing is that what ever lighting you use, be sure to place them in such as way that they cover the plants evenly throughout the garden.

Aquaponics Fish Tank

In the case a vertical aquaponics system, water is delivered to the fish tank through a tube coming from the tower channel outlet. The water is cleansed from the plants, and with a filtration device inserted before the channels inlet.

Like other aquaponics systems, the fish will need to be fed regularly (usually with fish food pellets or crickets). Nitrates and ammonia levels associated with the fish excrement need to be monitored, along with pH and water temperatures within the system.

Aquaponics Biofilter Options

DIY vertical aquaponics system

In most vertical aquaponic systems, a bacterial bio-filter will develop along the fish tank walls, becoming fish waste that converts to nutrients for the plants. With a larger system however, growers may need to add a separate filtration device for  the bacteria to populate. This will be placed between the fish tank and the pipe leading up to the tower’s channel opening.  Porous clay  pebbles such as Hydroton are placed in the device to encourage bacteria population. 

Garden Tower FilterIn some cases an additional filtration device is necessary to remove the larger waste solids the bacteria can’t break down. 

Aquaponics Pump

The submersible pump is a common aquarium or pond pump with a flow rate that varies in power determined by the size of the tower garden system. Fittings attached to the pump will receive the tubing that delivers the water to the top of the tower. The tubes are usually 1/2 to 3/4 inch in diameter and are attached to the channels by other fittings or even zip ties.

How to Build a Vertical Aquaponic System

aquaponic tower























You will have to insert the plants along the sides of the tower channel(s). There are a number of configurations you can use to place the slots for the plants to grow in. The important part is that the net pots don’t touch each other inside the channel as this could clog the flow of water and nutrients.

Cutting the holes along the tower channel sides can be done using a drill with a hole saw at a size of your choice (usually 3-4 inches diameter). Then use more PVC pipe to cut into small lengths that fit into the holes at a 45 degree angle downward. Next insert flexible net pots that will hold the grow media and plants growing at an upward angle.

You will need to insert shield material over the grow media and plants to prevent excessive flow of water into the pots. I’ve seen where growers use 3-4 inch segments of a vinyl blind stop inside the channel and above the net pots, fastened with a marine epoxy. Sometime a piece of sheet metal placed on the backside of the grow media pot will suffice. This is something you’ll need to monitor as you go since the flow volume in the tube channels aren’t equal at each level.

You can stabilize the towers vertically by using a 5 gallon bucket. This can be done by cutting a hole in the container lid the size of the channel bottom. Insert the tower channel and fill the bucket with sand or small pebbles to keep the tower stable. You’ll need to attach an end cap inside the channel walls using a marine epoxy to keep the water from leaking into the bucket. Then cut a hole in the the tower side to facilitate tubing that will take the water to the fish tank. Be sure to wash your tower to get out any debris before you attach it to the bucket.

4. Flood and Drain Aquaponics

Ebb and flow aquaponics system (also known as flood and drain ) is another alternative way to get your vegetables growing rapidly and vigorous. They are used commercially as well as at homes placed indoors and outside.

They are known for their ability to strengthen root oxygenation of the plants and a persistent circulation of water. Like most aquaponic systems, a flood and drain setup provides:

  • Nutrient-rich water for the plants.
  • Decreased stagnation of the circulated water.
  • Filtration of ammonia in fish excrement, that if left in their tank, would be toxic to the fish.

What is Flood and Drain Aquaponics


backyard aquaponics system

The main components of the Flood and Drain Aquaponics system are a fish tank, grow beds with media, and a water pump. The fish tank is where the water pump resides, and pushes fish waste through tubes/pipes into the grow beds. The grow beds house the plants and are filled with grow media such as Hydroton pebbles. The surface of these pebbles provides an environment of bacteria that converts the fish waste to nutrients through a process called nitrafication. The plants and their roots thrive because of these nutrients.

It’s important that the fish tank stays oxygenatated for the welfare of the fish, so devices are implemented to make that happen. First, the water piped from the grow beds downward into the fish tank with the aid of gravity, causes bubbling that aerates the water. An additional device called an air pump, can be used to boost the air into the tank through a tube creating more bubbles.

The final phase of the circulation is when the water in the grow bed, having been cleansed by the plants activities, is piped back into the fish tank.

Why is it Called Flood and Drain Aquaponics?

The water pumped into the grow beds reaches a predetermined stop level having flooded the area, and then drains it back into the fish tank. It is able to do this with a device called a bell siphon. This plumbing gadget uses air pressure changes to automatically release water when it rises to the top level. When all the water is drained from the grow bed the bell siphon stops the process and the flooding of the beds start up again. The beauty of this is that no timer is needed to keep the water moving through the system efficiently.

Flood and Drain Aquaponics System Design

This information is just to give you the basics if you’re getting interested in build one of these. There are so many variations in design that are possible. Determine the design type based on the region you live in, what kind of plants you want to grow, the systems location whether inside or outside, and your budget. So there is no reason to go over all the possibilities since it easier for you have a look on You Tube.

Here are the essential parts you’ll need to consider before you build your custom design.

1.Grow bed container(s) food-grade plastic containers that are BPA free, strong and thick material. Size is depending on your system but 30 X 16 inches and 12 inches deep is average.

2. Grow Media ( I prefer Hydroton) other possibilities are perlite, expanded clay pebbles, pea gravel

3. A Bell Siphon- these can be purchased online, or if you have plumbing skills, look on You Tube to build one yourself

4. PVC Pipe (schedule 40). One for flooding water into the growbed and another that receives the over flow of the bell siphon . * See Image Left

5. Tubing from the submersible pump attachment to the PVC pipe that floods the grow bed. Be sure the tubing is not clear to avoid algae forming in the water.

6. Tubing for air pump if you  use one. If that’s the case, an air pump too (dugh!).

7. A submersible pump- usually a common pond water pump will be sufficient….. but research the gallon per hour rating you’ll need for your design.

8. Container reservoir to serve as a fish tank where the submersible pump resides.

9. Fish that are edible like Tilapia ar Crappies for a medium size system and goldfish if you’re starting with an aquarium design.

10. Fish food- yes you’ll need to feed the fish periodically and fish pellets or crickets work well.

6. Chop Systems

Aquaponics Chop System

Aquaponics Chop SystemThe aquaponics chop system is the invention of growers in Australia. It means Constant Height One Pump and is known for its efficiency and healthy management of the fish. This system consists of a pump in a sump tank, a fish tank, and grow beds.

The “constant height” term refers to its fail-safe in regards of the fish tank water level. Water flows out the top of the tank using gravitation since the grow beds are placed below. This way the tank is always going to be full of water even if the pump breaks down or a pipe in the system fails. This is beneficial to the fish as they don’t have to deal with fluctuating water levels. So if the pump breaks down the water in the tank won’t dry up killing the fish. If the grow beds dry up it’s a problem but not nearly as devastating as losing your entire school of fish.

Using gravity to fill the grow beds minimizes electric power usage and extra wear and tear on the pump. The grow beds use a bell siphon or some type of auto siphon system to flood and drain the media beds eliminating the need for timers, an additional pump, and float switches. The grow media in the beds provide an environment for the bacteria to convert ammonia fish waste into nutrients. Some growers will add worms to their grow media as they are good at breaking down solids. The sump tank does wind up with larger waste solids so the sides need to be cleaned occasionally. Another option would be to place a solids filter device in the tube between the grow bed and the sump tank. It may slow down the cycle a bit, but I think it’s worth it.

The pump is stationed in a sump tank and pumps water up to the fish tank. The fish tank water gravitates down into the grow beds. In this way, the auto siphon has become the regulator of the entire water cycle system. In the CHOP system there is no need for one pump to move water to the fish tank, and another pump to move water back into the water reservoir container, in this case a sump tank.

One CHOP System Flaw

One drawback with the CHOP system is that the grow beds need to be exactly level with one another. Otherwise, they will not receive equal amounts of water. With 2 or 3 media beds you should be OK.  Just be sure to monitor water levels as you add grow beds.

Growers have changed the plumbing structure as a solution if they want more beds. The water from the fish tank is piped back to the pump sump. From there water is piped to each individual grow bed in separate tubes. This is done using additional fittings attached to the pump. Ball valves are placed at the fish tank outlet and every grow bed inlet to control the water flow. More power usage is needed of course, but overall it seems to work well.

Alternating Flood and Drain System

This type of system known as AFD is similar to the CHOP system. It’s different in that the pump is run by a timer. This way it can flood grow beds successively one after another using an index valve. This prevents all the water from being piped into the beds at once, therefore no need for a sump tank. When the timer stops for individual grow beds, water drains back into the fish tank. Then the pump moves on to the next bed via the index valve.

The system usually includes 4-8 grow beds and like the CHOP version, the grow media enables the conversion of ammonia fish wastes to nitrates that serve as nutrients for the plants. The grow beds utilize sheets of insulation (much like the DWC system) that house the plants.

The pump will need more power than the submersible pond type used for other aquaponics systems, and will cost more money. However, you will make up most of that not having to buy a sump tank.