The ebb and flow gravity feed system is the first system that I started with, and still one that I continue to work with today. The ebb & flow is like a natural system in the sense that it mimics the ebb and flow of the tidal system, which follows the moon. Similar to rivers and estuaries filling up when the tide creeps in, the plants in the growbeds and mangroves soak in the nutrients from the water then the roots dry out as the water gets pulled back to see, or the fish tank.
The graphic below shows a simple aquaponics design that we have worked with over the years. This system takes advantage of having a limited space to work in. It allows you to grow lighter rooting vegetables up top in the pipes like lettuces and herbs, while growing deeper rooting vegetables like tomatoes and bell peppers in the grow beds below.
In this type of system the growbeds are elevated above the tank to give the water a down hill effect. Basically the water is pumped from the fish tank to the grow beds, allowing the water to flow back into the fish tank. This system requires a pump to elevate the water and a timer to set the pump. When the pump turns on the water flows freely through the system. The grow medium in the grow beds acts a bio filter for the fish waste while the plants roots clean the water. A nice an easy way to allow the grow beds to fill to a certain level, giving the plant roots time to soak, then draining out again is to install a bell siphon to your grow beds.
Check out the following video to see a system similar to the diagram above in action using 150 gallon aquarium as a reservoir/fish tank.
The amount of time that you should let the water flow will range from farmer to farmer. A good rule of thumb is to let the system run a minimum of 20 minutes and hour during the heat of the day (for 8 hours) then let it slow down around sunset and rest at night.
Check out some of the following articles on Ebb & Flow Gravity Systems. [ Follow Us ]
