In flood and drain aquaponics, one part of the maintenance consist of cleaning the growbed. We don’t need to do it very often (maybe every 2 to 4 years) but it absolutely must be done. I already made a video on this topic here: https://melbourneaquaponics.com.au/clean-grow-bed/. A lot of information was covered there so today I will not be too specific but will simply share this new video where I cleaned a whole single aquaponics growbed.
I wanted to share this new clean-up with you so that you can appreciate the work involved. You can see the clogged media is forming a kind of cake where water can’t circulate freely. If water can’t circulate, the oxygen concentration will drop and the beneficial bacteria will die. In the video you can see that the cake is composed of media, organic matters, and roots.
- Don’t feed your fish for the whole day
Cleaning the growbed will release a number of organic matters and some of them will inevitably finish into the fish tank. Once agitated those particles will react and may release some molecules. This will affect the water parameters such as ammonia, nitrite and nitrate. The fish will therefore be stressed and if you have been following my channel for a while you know that we never feed fish that will be stressed (see the video there: https://youtu.be/vFeqzrORV_8)
- Turn the water pump off and disconnect the pipe from the growbed to the fish tank
We want to avoid the “charged water” to be drained into the fish tank. During the cleaning process, the fish tank will be isolated and the water pump off. The air pump will be on and as we didn’t feed the fish, the water parameters are good and allow us to keep the fish in good condition for hours into the same water without filtration.
- Connect a pipe from the growbed evacuation going to the classic garden
We will collect the organic matters and use them as a natural fertiliser for our classic garden. This will boost the production J
- Carefully remove all plants one by one and place them in a safe shady area
Now we can start to collect the plants away from the growbed. Note that the plants roots must be managed very gently and not be placed under direct sun exposition. Keep them in a safe (away from birds) shady and moist area.
- Collect 1/10th to 1/4 of the media in a container
We now need to make some room into our growbed in order to be able to move the media around. To do that we will remove 1/10th to 1/4 of the media and place it into a container/bucket or other.
- Clean the media in the growbed thanks to a shovel and a water hose (be very careful to not touch the growbed liner with the shovel)
Now it’s time to actually clean the media. Here we will use a shovel and a water pipe. The aim is to release all the organic matters trapped between the media particles. We want to obtain a fluid media and release all particles into the water going out into the classic garden.
- Clean the media into the container
The media placed into the container must also be cleaned. Place it under a water hose and agitate the media generically to release most of the clogged particles.
- Put the media back into the system
Once the media is clean you can put it back into the cleaned grow bed.
- Put the plants back into the system
The plants can now be planted back in place. Think of the positioning and light exposition. For a better productivity it’s better to place the large plants at the back and to separate the same species as much as possible to slow down the possible pest growth.
- Run some water through the growbed until the water flushing away is clearer
Before plugging the system to its original configuration we must drain the last organic matters away from the grow bed. Allow the water hose to come into the growbed and allow the water to run through the growbed and to the garden. Do it for a while until you see the water coming out of the growbed becoming clearer. You don’t have to wait until the water is completely transparent but you don’t want the water to be completely black neither.
- Unplug the water pipe going to the garden from the growbed exit and plug the original pipe going into the fish tank
The growbed is now cleaned. We can unplug the water pipe going to the garden from the growbed exit and plug the original pipe going into the fish tank. The aquaponics system is now in its original configuration.
- Turn the water pump on, observe the fish behaviour, check water parameters, check water colour.
We turn the water pump on. The water from the fish tank is now coming into the growbed. The growbed water level raise up and flushes back into the fish tank. The fish tank water will turn murky. You can check the water parameters but what is important is to check the fish behaviour. If everything goes well you should not be able to see them. If you see the fish at the surface, it’s time to renew some water and to apply the points detailed into this video: https://youtu.be/kqU-_KirFmU
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 🙂