Bell Auto-Siphon for Aquaponic Systems

Bell Auto-Siphon
(2 reviews)
2.00 KGS
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A Bell auto-siphon is the heart of an Aquaponics system, though it can also be used in an hydroponic setup.


Flood and drain cycling in ebb-and-flow aquaponic systems can be controlled by electronic timers, which regulate the activity of water pumps, or by non-mechanical devices called automatic siphons. These auto-siphons can start and stop water flow on their own, depending on the level of water surrounding them. The bell auto-siphon is one of the simplest methods.


An auto-siphon comprises several components:


  1. A vertical standpipe that projects upwards from the bottom of the aquaponics grow bed. This pipe regulates the maximum water level in the grow bed. THe vertical standpipe is supplied with a uniseal to seal around the pipe as it penetrates through the hole at the bottom of the grow bed.
  2. The "bell" pipe that fits over the vertical standpipe and that has a diameter double that of the vertical standpipe. It is also slightly longer. This pipe has a sealed cap on top, and opening at the bottom to let the water in to the chamber
  3. A Service Pipe (gravel guard) that fits over the bell pipe and is there to stop gravel or other grow nedia from blocking up the bell inlet holes. The gravel guard has an inspection lid on top that be screwed off or on when required.


How it 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 fll, 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 inlet holes at the bottom of the bell.
  • Air is then forced through, and as a result the siphon is broken, resulting in the grow-bed beginning to fill again; the cycle then repeats itself



Service Pipe       = 330mm (h) x 130mm (d)

Bell Pipe            = 310mm (h) x 50mm (d)

Standpipe          = 410mm (h) x 25mm (d)


Standpipe is supplied with a uniseal. Adjust height of pipe to suit required water level of grow bed. The rest of the pipe will protrude below the grow bed down to fish tank


  • 4
    Concern no installation instructions.. No connector as explained below

    Posted by Derick Sinden on 28th Jan 2022

    Recently purchased your Bell Syphon valve. Concern is how to install the 25 mm drain pipe to the base of my PVC growbed. Need a 1 -3/4" Male adapter (thread to slip) 1 - 3/4" Female adapter (thread to slip) 2 - #18 o-rings. No luck with Builders Warehouse, Buco, or On Tap. Any suggestions.

  • 5
    Excellent Product,Service and Delivery. Highly recommended!!

    Posted by Farouk on 6th Jun 2018

    I will most certainly do business with MyAquaponics again. Delivery was extremely fast and besides the colour of the bell siphon being different, it was a great product.