Backyard Aquaponics
A place to discuss aquaponics

I've built the attached siphon. Note that I didn't depict the inflow (a constant rate pump that is never turned off) or the emergency drain (located above water level B). About 20% of the time, it works perfectly, and I believe I am "close".

However, about 80% of the time, after the siphon primes (at water level B), the box drains down to water level A, and then the siphon -- instead of stopping, as expected -- continues to "gurgle" at about 50% of the full-siphoning rate. The water stays in equilibrium at level A, with the inflow maintaining constant rate with the gurgling siphon, and my water line never rises back up to B.

What's going wrong? Would another couple of elbows somewhere solve this?
Please help, I'd love to get this working today
Thanks in advance, --Lee

Whoops, just re-read my post:
All of my water levels I referenced are "backwards" in the diagram. In the diagram, A is the high-water mark, and B is the low-water mark, but when I wrote the post, I referenced B as high-water, A as low-water.
My bad, sorry for confusion!

If the siphon is not shutting off properly and reaches equilibrium with the water level at the bottom, then your water inflow to the bed is too fast. You can put a bypass in (A T with a ball valve to divert some excess flow back to the tank where the pump is, just open the valve a little to let some flow go back to the tank with the pump and that will reduce the flow into the grow bed a little.) This allows the pump to keep working efficiently while still allowing you to reduce the flow to the grow bed.

Anyway, if you reduce the flow into the grow bed just a tiny bit you will probably get reliable siphon operation.

What you've built is essentially a "no holes overflow".... and yes ... you'll have enormous difficulties keeping it primed...

Build a standard bottom draining auto-siphon.... or a loop siphon...

Hay Rupe, it's not going over the top of the bed, Just the picture doesn't show much level above the siphon. It's really just a goose neck where the top of the neck is going through the side of the bed.

Drawback is they can't adjust the height of the flood level since that has been set by the hole through the side of the bed but it sounds like they just need to adjust the inflow rate and the siphon will be able to cut out better.

Even so TCL... it's almost a loop siphon... except that it's not bottom draining... and I think will always have problems, or be difficult to manage...

Hey

your siphon looks a lot like my overflow siphon

I have this on my starter systems and on my outdoor bed system

they have worked perfectly since day one...... here is a picture of how mine are set up

this one shows the outlet going into an NFT pipe but can go to a sump tank or fish tank






jT

Yep... but your's is positioned right to the bottom DT... and has a surrounding pipe... that helps draw the water up into the siphon...