Today we are visiting Paul who built an aquaponics system on the side of his house. The surface is very limited but Paul is still able to grow a nice quantity of food. Up to one meal per day in summer! Paul reach this impressive productivity thanks to a hybrid system. The system is composed of a fish tank, a sump tank, a flood and drain growbed and a Nutrient Film Technique (NFT) system.

Fish

Paul is growing silverperch in his fish tank. He got some decent size fish, some of them are 4 years old and reach the plate size.

Vegetables

Paul is growing a variety of leafy vegetables in the growbed such as spinach, beetroots, silver-beet, Vietnamese mint, Chives… In the NFT system Paul is growing lettuce (approximately 20 of them) and is picking the old leaves as they grow. In summer he is able to pick the equivalent of one little lettuce meal per day. The NFT system has been smartly placed along the side of the house. It doesn’t take much surface and is placed in height so it is exposed to the sun. Paul insulated part of the pipes to moderate the water temperature raise during summer. This little NFT is efficient. The aesthetic could maybe be improved by covering the white pipe with hessian fabric to give it a more natural look. Paul used PVC pipes, he could have used PVC gutter as well as they present the advantage to have a flat base which spread the water nicely along the base of the pipe and limit roots clogging.

We note that the NFT system has been well designed as the extremities can be opened in order to clean the pipe. The extremity of the pipes are open and unfortunately no net are placed which leave opportunity for mosquitoes to spawn in it. I would strongly recommend to close those pipes in order to avoid mosquito infestation.

The fish tank is composed of an IBC tank cut and insulated with nice painted wooden boards. The top of the fish tank is covered with a wooden cover. Part of this cover ca be lifted and the fish can be directly seen.

The growbed is made out of an IBC cut at approximately 35cm height. Paul placed a mesh filter on the incoming water from the fish tank in order to capture the largest fish particles.

In terms of Media Paul choose to use 20mm scoria. The advantage of this type of media is that it doesn’t clog as quickly as the 7mm. The down side is that it doesn’t offer the exact same surface area so the efficiency per volume is decreased. Growing plants from seeds is also less successful in a 20mm scoria as the seeds are moving between the media, the space between the rocks is large and the seeds physically move with the water movement. In this case the success rate will be minimized compared to a classic 7 mm scoria. A good alternative is to germinate the seeds aside and to plant seedlings directly into the setup.

Sump tank

The sump tank is composed of a simple black plastic tank equipped with a 3000 L/h pump. The pump is powerful enough to raise the water back to the fish tank and another pipe is raising the water to the NFT system. I would recommend adding few small fish type “Gambusia” also known as mosquito fish into the sump tank simply to avoid mosquito spawning in it.

Thanks to Paul for the visit, this is a good example of a low scale efficient hybrid aquaponics design.

Welcome here! If you are new, you will probably be interested to discover Jonathan’s six steps to build and manage an Aquaponics system. Click here to access for free! Thanks and good reading 🙂