Backyard Aquaponics
A place to discuss aquaponics

Hi All,
IMHO and experience, Regardless of the style of Auto siphon construction, Bell Mouth (aka 'Affnan'), Air bleed tube or straight Tantalus, the most important consideration for a working Automatic Siphon is that it MUST BE AIRTIGHT!
Not just water tight; the introduction of ANY amount of air to the top of the Bell will stop the action, no matter what else you do. Increase the flow to get it started, fine . . . but it won't stop, decrease the flow to stop it . . . air gets in . . .; and it won't start!
Every siphon I have made works from the get go, because I ensured that all joints were glue fixed AND sealed. Have never had any problems. Intermitent problems people get with them I'm sure has to do with air tightness and bits of Bio-film and the like either sealing or opening air leaks when moving around. You also have to stop the Bell from jumping and moving around, especially at the draw down end of the drain cycle. The bell can jump enough to break the siphon earlier than expected and on non-predictable occassions. I either use a Foam packer under the lid of the fixed Media shroud, or for side outlet, I hole saw a sized opening in the base of the Bell tube that 'clicks' over the outlet pipe fitting to prevent it from lifting etc.
Anyway, here are some photos of the Siphons I make and use.
Cheers IanK

I have a small demonstration system that I use to explain the workings of our larger system to a regular stream of visitors and have knocked up this bell siphon to demonstrate how it works.
While I find the bell siphons reliable I have started playing around with the affnan design for the primary reason that they require less water to activate and therefor won't need a bigger pump when it comes to expanding the growbeds (hopefully)

Thought that a drawn section may be usefull for reference.
It's a Zipped PDF.
This one is for the recently fabricated IBC DIY, so dimensions may not be appropriate for deeper Grow Beds. This one has tested OK yesterday without any Media, just cycling water.

Cheers IanK

What no flouts allowed?

Nice work Ian
I totally agree about the siphons being airtight
And I agree that most siphons are pretty much alike the only real difference that I see with Affnan's design is the area of the internal standpipe is greater than the area between the inner wall of the bell and outer wall of the standpipe. This is the key to starting the siphon (and with less water)

Not if they waste good eskies!!!

Loops!

Roadside pickup and it had a hole in the top (which proved useful)

Anyway you could only get 2 sixpacks and the ice in it.

cheers on the loops

How reliable are those?

Loops work really well and reliably for small bins/tubs... and half barrels...

I've had mine running on my blue barrel system for years....

+1 for loops, can't be simpler.

Quick and dirty loop siphon, not pretty but it worked.

Here's one, I know some people like to use an elbow at the beginning to help the backpressure, and maybe to help the loop stay out of the way of things.

Hi RupertofOZ,
I have been looking at what sort of syphon for my new system and was thinking maybe the loop is less technical for my small brain, but you say only small containers. Not half IBCs or long 500litre trays?
Dale

Bridges !