Backyard Aquaponics
A place to discuss aquaponics

I'm setting up a system that will hook up three growbeds and run them into a common drain and auto siphon. This is similar to the design TCLynx has for fingerlings.

To ensure good operation, I need the tanks to drain fast. Any idea of the best/largest diameter siphon I should use?

How big are the GB.
How big is the FT
How fast do you pump the water in?
How far is the vertical drop (outlet) on the autosiphon?

If you've started setting up the beds, a Piccy would be very helpful, otherwise a sketch (even in mspaint) would be helpful, but we'll need some numbers.

I use a 1" pipe, some others use a 40mm 1.5" pipe... haven't heard of anything bigger or smaller than this.

I have 13mm siphons, and 32mm siphons.

As KP said, Numbers!

Kuda you forgot ;how long is a piece of string;

The answer is 42.

Answer to what Duff?

Milne: Twice as long as from one end tot he centre! I thought everybody knew that!

Do witch end though

to Dawn French

I was asking more in terms of if the siphon pipe diameter is too large, then it will not work properly as a siphon. Or am I wrong? I think 40mm is about as big as you'd want to have. The system is only small, the three GBs together will be about 150 lts. I suppose 20mm should do it.

20 25mm is okay. The larger pipes need more water running to get them to work. I use a lot of 40mm but have a 10000lph pump feeding the gb's. You can always upgrade later.

I'm using 100mm for my no-holes over flow based valve. Relies on similar principle to the auto siphon but the emptying is controlled by a counter weight.

Any size pipe will siphon.
but the siphon NEEDS to match the flow. If the flow exceeds the siphon, your siphon will start, and be too slow, and the bed will overflow (uncommon, but possible, I've had it happen)
If the siphon exceeds the flow, then it will never properly trigger, and so the outflow will match the inflow, and the GB will remain full.
So there is both a minimum and a maximum, but they depend on other factors, such as inflow, drainage resistance, length of outlet drop, possibility of airlocks... all sorts of things.
Hence my request for these figures.
Siphons are flexible, but not undefeatable.

Isnt LKB using a 90mm siphon?

As kuda says - you just need the flow to start the siphon, but not overwhelm it.

My 13mm siphons can take the flow from a fairly gushing 19mm pump line.

The answer to the "Ultimate Question"
The answer To Life itself, The World and The Universe!

Oh Yeah... The ultimate question is " What is 7 X 6?"
Therefore the Ultimate answer is "42"

Hope that clears it up!

(Hitch Hikers Guide to the Galaxy )

Yes... I asked a touch prematurely... Without thinking... I meant, 42? What's 42? 42 what? huh?

my memory of the book is not what it could be