Build Your Own Aquaponic System

Building your first aquaponics system can be a daunting task. It can seem like there are a million options, and two million things to remember.

Really, it is simple.

Here is a comprehensive guide on how to build your own simple aquaponics system. Simply follow the steps, and design the system that you want.

Conditions

First, you need to make sure that you have the right conditions for the construction and maintenance of an aquaponics system.

Space is the most important factor to begin with. An aquaponics system needs room, and a good minimum size to allow is four cubic feet. This should allow enough space for a 100 gallon fish tank, a 10 inch deep growbed, and the room to work in and around the system. This may sound obvious, but remember: the bigger the system, the more space you will need.

Of course, if you are designing a simple mini-aquaponic system (like this) with a small aquarium feeding directly into a supported growbed, then the amount of space you need will be vastly reduced. The key is to plan accordingly.

Sunlight is probably the most important factor after space. In aquaponics, the ideal sunlight configuration is full exposure for the growbeds, and reduced exposure for the fish tank.

A greenhouse can be a good place for an aquaponics system, but beware of algae.

The more sunlight on the surface of the growbed the better, as this will allow your plants to flourish. However, although fish also fare better with access to light, it is not advisable to place your fish tank in direct sunlight. This encourages the growth of algae and other surface dwelling aquatic plants. This is undesirable, as it will remove precious oxygen and nitrites from the water, inhibiting fish and plant growth.

So plan to build your aquaponics system outdoors, with access to direct sunlight, or indoors, preferably next to a south-facing window.

If you do not have access to direct sunlight, don’t worry. You can purchase grow lamps which will serve just as well: but be aware that this will increase your running costs, and becomes less feasible for larger systems.

Other factors to consider are proximity to a power outlet, for the water pump (and possibly grow lamps); and temperature, which will affect the growth of both your fish and your plants.

Fish Tanks and Growbeds

The next step is to select the size of the fish tank you will be using. A good minimum size is 100 gallons. This will be big enough to house several good-sized fish, but also transportable and flexible in terms of system design.

This can be almost anything, as long as it is non-metal and non-toxic. Glass aquariums are an option, although these are heavy, fragile, and can promote algae growth. Plastic is a lighter and much preferred alternative, although there is the minor drawback of reduced visibility.

Glass fish tanks look pretty, but are much more difficult to transport than their plastic counterparts.

The same goes for growbeds, which again, should be plastic. The ratio of growbed to fish tank (in gallons) should be about 1:1, although this is flexible. Some aquaponics guides suggest that a 2:1 growbed to fish tank ratio is ideal, but the nature of a ebb and flow system means that without intermediary measures- such as a sump tank- the water in your fish tank could periodically reach dangerously low levels. A 1:1 or even 3:2 ratio is better, especially for smaller systems. There are several other reasons (including potentially stunted fish growth and water levels), but this is the most important.

So a 100 gallon fish tank, for example, should be accompanied by a 100 gallon growbed, or two 50 gallon grow beds. The grow beds should be rectangular, and deep enough for an outlet, media, and root growth (10-12 inches is a good minimum).

Support

Once you have your fish tank and your growbed, then you can begin to assemble your system. Support is an easily forgotten but crucial part of aquaponic design. In most systems, one of either the growbed or the fish tank has to be raised above the ground.

Remember that water, and growth media (like gravel) is extremely heavy, and as a result plastic containers can become warped very quickly and easily in an aquaponic system. Sometimes dangerously. The way to avoid this is to preempt it, and either find a stable base for your raised container, or be willing to build a simple frame for support.

This is a small step, but one that if carefully considered can reap rewards and reduce cost over time.

Pump

The next vital piece of your aquaponic system is the pump. As a general rule, any pump that is sold for use in an aquarium or pond is acceptable for aquaponics, although try to check and avoid any pumps which may contain excess metal, or are known to wear and break down quickly.

You want a pump which is powerful enough so that the water in your system circulates roughly every 15 minutes, or four times an hour. This is where system design can get complicated, but there is a simple formula to help you calculate the required ability of your pump:

Take the size of your growbed (100 gallons in our case) and subtract 10% (90 gallons), as you will not fill it to maximum capacity. Next, divide by two (45 gallons) as media will take about half of the growbed space. Then, subtract 10% again (~40 gallons) as not all of the water in the growbed will drain. Finally multiply this figure by four (160 gallons) which is the amount of times per hour we want to cycle the system. This is the number of gallons your pump should be able to pump per hour at the height of your system. 

So for a system which has a 100 gallon growbed and sits 4 feet off the ground, you would want to buy a pump which pumps 200 gallons an hour at 4ft head pressure.

Your water pump should be powerful enough, and reliable.

Other features are worth considering, such as whether the pump is adjustable flow rate, and whether it has an inbuilt filter, but power is the most important aspect when selecting a pump.

Filters and Sump Tanks

One consideration you should have when designing your system is whether you will include a filter. Filters have several obvious benefits, the biggest being that filters prevent clogging, encourage nitrification, and vastly reduce the need for cleaning your system. A system without a filter may well require occasional cleaning, especially of the water pump.

Filters come in many shapes and sizes. The most common are radial settlement filters, swirl filters and biofilters. Radial settlement filters direct the flow of water to allow heavy particulate waste to settle to the base of the filter. Swirl filters have a similar effect, although they direct the heavy waste rather than let it settle. Biofilters are effective for both heavy waste and lighter suspended waste, and they use solid media to trap any waste and allow it to be broken down by bacteria.

If you are using  gravel (or similar) media, then your growbed will act like a biofilter, and it may be that you do not need an extra filter. The beauty of external filters is that they can be added at a later date if you decide it is necessary, and can be designed according to your requirements.

Your growth media is also your best biofilter.

Other, smaller measures can be taken if you do not want to go to the trouble of building and incorporating a filter, such as sponge filters (just a small piece of sponge) under your water inlets, and mesh gauze to protect your water pump.

A sump tank is basically an overflow tank which can either be used as a settlement tank for solid waste, or as an overflow tank to regulate the water levels in your fish tank.

If you have followed the growbed to fish tank ratio outlined above, then you will not need a sump tank, as the water levels with not vary dramatically enough to potentially cause stress to your fish.

However, if you would like to include one, or if your ratio of growbed to fish tank is closer to 2:1 then you should consider including one. You will need another plastic container, which should be big enough to match the amount of water in your growbeds. For example, if you are using a 200 gallon growbed, then your sump tank should be about 100 gallons (as at least half of your growbed will be filled by media).

Ebb and Flow vs. Continuous Flood

Unless this is the first thing you have read about aquaponics (in which case, welcome), then you will probably have come across the ebb and flow (also known as flood and drain) and continuous flood discussion. There is also a third popular option, often used in hydroponic systems called nutrient film technique (NFT), but this is not relevant to this particular guide on simple growbed aquaponics. However, NFT can be incorporated very successfully into many systems, and is worth researching if you are interested in expanding your aquaponic knowledge.

Firstly, continuous flood is the simplest and easiest to use. This is simply a growbed which holds a constant water level, allowing plants access to the nutrient water at all times. The growbed can either contain growth media, or a floating raft to support the plants. However, this method will cause root rot and eventual death of many plants, and so your plant options become limited when you are using this method.

The outlet on the left is for a continuous flood system; the outlet on the right (covered by the bell siphon) is an ebb and flow design.

The second (and most widely used) option is the ebb and flow design. This method uses a timer, or a siphon, to fill and empty the growbed of water at regular intervals. This will support the growth of the vast majority of vegetables and plants, and it is recommended that you use some version of this design.

Both loop siphons and bell siphons are relatively easy to construct, cheaper, and more energy friendly than automatically timed pumps and valves, and so they are the preferable option for ebb and flow aquaponics. Here is a great guide on how to construct loop and bell siphons, and why you would use each one.

Plumbing and Construction

Finally, putting everything together. Plan carefully, and make sure you know what you will need to order/pick up from your local hardware store or from the internet. For most systems, you will need waterproof seals (such as Uniseals) and at least one meter of PVC pipe in your chosen width (about 1″ should be adequate for most small and medium sized systems). As well as this, you will probably need elbow joints, tap valves, and- if you are using two or more growbeds- one or more T-joints. Remember that everything should be plastic: no metal.

As for tools, the only things you should need are a saw and a drill. The saw will be used for cutting the PVC pipes to the correct length, and so a small, cheap handsaw is more than adequate. The drill should be electric, and you should be prepared to find and purchase the appropriate hole-saws to go cut the holes for your waterproof seals.

The Life Aquaponic toolkit. Less than $60 dollars to assemble.

It is also advisable to have sandpaper, and a small craft knife. The sandpaper is to smooth the different joints and seals after they have been formed, this helps with the overall fit and prevents leaks in the system. The craft knife is simply a cheap but useful piece of kit to have around, with many potential uses.

Get Going

We hope you enjoyed this guide on how to build your system. In the coming days and weeks we will release more guides on how to get your system running, what media, fish, and plants to use, and many other exciting topics.

If you have any questions, or need help designing or building your system, please contact us. Send us an email, or message us on Facebook or Twitter.

Happy building!