Aquaponics How To

What do I need to Consider?

Which System?

There are 3 main types of Aquaponics Systems, media based, Deepflow and NFT

Media based which is the most common design used in backyard systems uses either gravel or clay pebbles. The plants are sown directly into the media. Gravel is used in the flood and drain system where the grow beds are flooded and drained periodically allowing water to circulate through the system on a regular basis. Expanded clay pebbles are used in the continuous flow system. The clay pebbles are designed to absorb water and keep the plant roots moist.
Deepflow/raft is mainly used for commercial systems. The media used is water and rafts made from styrofoam or a floating board with holes for pots to allow the plants to sit in where the roots are always immersed in the water.
Nutrient Film Technique can be used for backyard or commercial but is the least commonly used. This is where the plants are in pots and a small amount of water is trickled through the base of the channel where the roots access the water.

Pump

It is best if your system is designed to only use 1 pump. This is obviously  much more energy efficient, and fits in easily with the environmental advantages. Ensuring your fish tank is lower than your grow beds in your design will ensure that only one pump is required and that is in the fish tank. The water can then be pumped from the fish tank into the grow beds and then the use of gravity to allow the water to flow back into the fish tank.  Remember it is a recirculating system so it makes sense to make it simple and easy. In a small backyard system you do not require a huge power pump. We have a 200watt pump in a 1000 litre fish tank going to 2 grow beds and it works great. Just make sure it is designed for continuous operation.

Water

To enjoy a successful system you need ensure that all chlorine is removed from the water. Use of a filtration system, adding water additives to neutralise the water or exposing the water to air and sunlight for a few days will all do the trick. Having clear water helps you to keep a check on your fish.
You also need to keep the oxygen level up for the fish to survive. A Venturi connected to your pump in the fish tank can usually create oxygen for the fish. For bigger and commercial systems air diffusers are used to create bubbles thereby creating oxygen.

The temperature of water is also vital for your fish survival. The sudden drop or increase in water temperature can be a shock to the fish. Keeping the temperature at the right level for your type of fish is important to avoid losses.

Testing the water is the perfect way to understand and see how your system is performing.  Testing for ph, ammonia, nitrite and nitrate are the most important one. For ph the optimal range is between 7 and 7.5 for fish, plants and bacteria in an aquaponics system. Maintaining good water quality is the key to successful fish keeping. You can get test kits from most Aquarium shops. Try to keep good records as this gives you an indication on how your system has been working.

For questions on water testing see the section Water Questions

Photos are of aquaponic systems built and/or maintained by Martin and Kerri