The Bell Siphon is one of the most important pieces of control equipment in the grow bed of a flood and drain aquaponics garden. Although most inside aquarium driven systems use the continuous flow style, there will always be exceptions where the unit can be separately supported to hold the weight both of the deep grow bed substrate and the water as it fills the pan.
Although the mechanics of a Bell Siphon are quite rudimentary, they are not particularly intuitive for someone new to this pursuit. In essence it is a control valve that allows the water to fill to a particular point in the grow bed, then causes all the water to flush away. The Bell Siphon does this without employing any moving parts so it is quite efficient and once properly tuned, quite effective.
Simple Bell Siphon video graphic
Best Ever Bell Siphon video graphic design
Best Ever Bell Siphon video – Actual unit construction and implementation
The Bell Siphon can be Built at Home
As you can see from the above three videos, there are quite a number of ways that an effective Bell Siphon can be constructed. The problem for those who build them from parts purchased maybe to get the right diameter and other dimensions so the system works flawlessly. This may take a bit of experimentation. But once you get it right, copying the working Bell Siphon can be done over and over again.
For those who don’t have the knack to do it yourself, these can be easily purchased with the fittings. Once in hand, the Bell Siphon can be easily installed into the grow bed and should work fine as long as there is no debris entering the tubes along with the water. The outside protective tube must be large enough to allow the water to flow easily and cover the output downspout to create the siphon condition that is used to drain the grow bed as low as possible. This requires that there be enough openings in the protecting tube to let water flow fast enough, but that they are not so large as to let any of the substrate through to block the inputs of the Bell Siphon.