Instructables
Picture of Make a Bell Siphon
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 a 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.
 
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Step 1: Parts and Tools

Picture of Parts and Tools
Here's what you will need to make your own bell siphon:

Parts:

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
Tools:
  • Drill or dremel
  • Drill bit (1/8")

Step 2: Preparing the Dome and Guard

I created a guide that you can use to make clean and equally spaced holes around the bottom of your gravel guard and bell dome.  First download the Bell Holes Guide Document and print it.  You will likely get an error message saying, "The margins of section 1 are outside the printable area of the page.  Do you want to continue?"  Click Yes.  Cut out the two guides, wrap each guide around the bottom of your PVC pipes (the 3" gravel guard, and the 2" Bell dome), and tape them in place.  Use the guide to drill holes around the bottom of each pipe.  Remove the guides and clean up any left over PVC dust or tags.
barry_dh8 months ago

Thank you for sharing this. Unfortunately I'm not able to download the Bell_Hole_Guides.doc, its says "Request forbidden by administrative rules."

Could you please email it to me, barry_dh@yahoo.com

Thanks a lot :)