Siphon won't initiate

[Michael Brewer]

Hello there!  I'm new to the group, but am excited to learn more about aquaponics here!

I've got a small "Barrelponics" system that I've set up to try and learn about aquaponics and work the bugs out so that I can take it overseas.  I modified it slightly because I want to set up systems with no moving parts, and that system uses a toilet flush valve to flood the growbeds.  

I switched to a simple, u-curve autosiphon and it works good- when it initiates.  I can get it to initiate if I increase my inflow, but that causes my growbeds to get flooded to often.  I am shooting for a flood cycle every 45 minutes, and right now it is just under 20.

Does anyone know a way to get an autosiphon to initiate regardless of inflow?  Extra reservoir, extra u-curve, submerging the outflow in water, etc?

[Alex Veidel]

I'd imagine having a smaller standpipe would help. Also, if it doesn't already have one, add a funnel of some kind to the standpipe, it will help collect water faster, resulting in a lower requirement of inflow to trigger the siphon.

[Harold Sukhbir]

Hi Michael,

Try reducing the drain pipe end to 1/2 its existing size. You can attach a simple reducer to the end of the drain pipe. This will cause the siphon to start faster will less flowrate.

[Michael Brewer]

Thanks for the advice and quick responses!  I will try adding the reducer.  Here's a picture of the siphon, just in case anyone notices anything else about it.  Right now it is 1" PVC.  If I have it cycling every 20 minutes, it works like a charm, but I need to dial it back to every 45 minutes if possible.

[Harold Sukhbir]

Hi Michael,

A 1/2 inch reducer placed at the exiting 1 inch outside of the base of the barrel will reduce your fill/drain time. You could place the reducer in a removable coupling so that it can be removed for periodic inspection/cleaning if need be. I have run 1/2 fittings and pipes in AP in an AP system for almost 3 years without clogging or having the need to clean.

If the 1/2 inch fitting still demands a flowrate with too short of a fill time,(around a 30 minute cycle) and you wish to reduce it further, you can insert a tight fitting silicone tube into the reducer decreasing its diameter even further, to arrive at your ideal fill/drain time.

[Michael Brewer]

I will play around with that.  Thanks for the advice!

Harold Sukhbir said:

Hi Michael,

A 1/2 inch reducer placed at the exiting 1 inch outside of the base of the barrel will reduce your fill/drain time. You could place the reducer in a removable coupling so that it can be removed for periodic inspection/cleaning if need be. I have run 1/2 fittings and pipes in AP in an AP system for almost 3 years without clogging or having the need to clean.

If the 1/2 inch fitting still demands a flowrate with too short of a fill time,(around a 30 minute cycle) and you wish to reduce it further, you can insert a tight fitting silicone tube into the reducer decreasing its diameter even further, to arrive at your ideal fill/drain time.