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Interesting! Kids Can Become Young Scientists by Experimenting these few Easy Steps!

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Hello world

blind man

What is a Bell Siphon? Something in a bell-shaped form to experiment? No!

A bell siphon is used in ebb and flow aquaponics and hydroponics systems in order to regulate the flow of water. In an ebb and flow (also known as flood and drain) system water is pumped into the grow bed. At a specific point (usually 2 inches below the surface) the water drains via the bell siphon. When the water reaches the bottom you will hear the classic gurgle indicating the end of the drain phase. The process will then repeat itself over and over again. The bell siphon is such an important part of any ebb and flow system that getting it right is crucial. In this instructable, I'll show you how to make your own, and tweak it to your needs.

Well, here are a few steps to create a Bell Siphon:

Gravel Guard

1 - 3" PVC pipe (approximately 12" long)

Bell Dome

1 - 2" PVC pipe (approximately 10" long) 1 - 2" PVC cap

Bell Siphon

1 - 3/4" PVC pipe (approximately 6" long) 1 - 3/4" to 1 1/2" bell adapter

Grow Bed Connections

1 - 3/4" Male adapter (thread to slip) 1 - 3/4" Female Adapter (thread to slip) 2 - #18 o-rings

Drain Pipe

2 - 3/4" PVC pipe 4" long 2 - 3/4" 90o elbow


Drill or Dremel

Drill bit (1/8")

Bell siphon theory

A bell siphon consists of several components, beginning with a vertical standpipe (schedule 40 PVC) that projects upward from a bulkhead fitting in the bottom of the aquaponic grow-bed. The standpipe regulates the maximum water level in the grow-bed. A drainpipe extends from the bottom of the bulkhead to the fish-rearing tank. As the water level in the grow-bed exceeds the height of the standpipe, the water overflows through the inside of the standpipe and the drain directs the flow of water to the fish-rearing tank. An additional pipe (the ?bell?), which has a diameter twice that of the standpipe and is slightly longer than the standpipe, is fitted and glued with a cap on one end. Notches, or ?teeth,? are cut into the bottom end of the bell, and it is placed teeth-down over the standpipe. A hole is drilled in the capped end of the bell, and an air tube is inserted into the hole. This air tube, or ?snorkel,? acts as a means to break the siphon; it extends down the length of the bell, ending just above the level of the teeth.

How a bell siphon works

? As the water level rises in the grow-bed, water is forced through the teeth on the bottom of the bell and up between the walls of the standpipe and bell.

? As the water level exceeds the height of the standpipe and the drain begins to fill, a siphon is created.

? Most of the water in the grow-bed is then drained by the siphon until the water level reaches the height of the teeth and tip of the snorkel. ? Air is then forced through the snorkel, and as a result, the siphon is broken, resulting in the grow-bed beginning to fill again; the cycle then repeats itself.

Using a bell siphon for aquaponics has become a very popular option, especially with the ebb and flow setups becoming more and more common. This is because siphon devices like these offer many benefits when it comes to aquaponics. One of the most obvious benefits is the improvement in oxygenation to the roots of the hydroponic plants. In bell siphon grow beds, the action of the water draining draws oxygen through the full length of the root aiding in plant growth and the overall health of the plants. This compliments the ebb and flow?s benefits associated with flooding the roots with hydration and nutrients and then removing the water so oxygen can reach the roots. Another benefit to both the bell siphon grow beds and the fish is the constant and consistent movement of the water. Regular water flow improves oxygen in the water and prevents water stagnation.

One of the biggest benefits of using a bell siphon for aquaponics is that the process works automatically. This is really the major selling point for this style of siphon. Unlike other methods used in ebb and flow aquaponics systems, the bell style of siphon controls the flood and drain cycle for you. No need for a timer, no need for manual draining, no need for additional drainage equipment. Once the siphon is properly installed and adjusted for your unique situation, just add water, and it takes care of the rest. As water fills the grow bed and the bell the process begins. Once full, the siphon starts draining right away, and after the draining has finished water can start to fill up again. This prevents extra work on your part while ensuring that your aquaponic system functions at maximum efficiency. It is really the perfect solution once you get tweaked to work properly.


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