Backyard Aquaponics
A place to discuss aquaponics

Is there a thread that explains flood and drain in detail?
I am wondering what apparatus is in the drain hole?

2 small holes in the standpipe (6-8mm)

The pump turns on and floods the bed
The water reaches the height of your standpipe and overflows until the pump turns off
The water slowly drains out the two holes in the bottom of the standpipe

Holes get drilled as low as possible - in this picture I drilled them into the black nut angling down


In this example I drilled them into the white pipe


BOTH OF THESE EXAMPLES DON'T HAVE MEDIA GUARDS - DON'T FORGET!

can you incorporate syphon and flood and drain in the same standpipe?

I think so? But don't quote me on that.

If the pump is on a timed cycle and has enough power to make the standpipe overflow, then yes you can make a bell siphon.

If it doesn't work you can have 2 standpipes - one with small holes for Flood and drain - one with no holes for siphon. Just switch them over.


This white connector screws into a bulkhead fitting and the white pipe can just pull out and change over.

Thanks J
I had been wondering about whether it is possible to use a siphon.
It's AP101 but I had never tested it myself.

I'm not sure a siphon and a F&D standpipe would work well together. (I seem to be headachey and clogged up this morning so not sure my brain is working at all so I might just be confused )

Normally with a siphon system you have the pump running 24/7 - the siphon (Bell or Afnan) provides the F&D cycle. It seems to me with both in place, (i.e. a F&D drain pipe with a bell surround) the bell would start the siphon and never break siphon - the small holes needed for the F&D pipe would be below the siphon holes and will never be out of water.

If you bring the holes above the level where the siphon holes are the siphon will not start. Or maybe it would take longer to start due to having to wait until the water rises above the drain holes.

Having 2 different stand pipes (as above) might be the best idea if you want to be able to change - but you'd need to pipe height etc or you'd have both systems trying to work. I think you'd need to leave the siphon cover in place all the time - it's going to be a pain if you have to remove media from around the pipe every time you want to swap over systems.

Just my (possibly confused) thoughts on it...

So an auto siphon IS a flood and drain system?

Yes....

And some people do utilise the weep holes in the standpipe...as used in a timed system...

On the basis that if the pump, or power should fail... the grow bed drains back to the fish tank...

I have drain holes in my standpipes and I can put the bells in and the syphons work fine. But I prefererably run mine CF.

If you're running constant flood Charlie... why bother with the weep holes...

Is it only to allow the bed to drain if the pump/power fails???....

Could you have an operating auto siphon with small weep holes (<6mm) in the stand pipe just in case the power failed?

I have a 700ltr FT with a 300ltr GB and a 4000ltr/hr pump....I should be able to pump more water into GB than can drain via the weep holes right?

Yes, and yes...

is anyone else doing it this way?

Yep... there are other members who use siphons.. that have weep holes in the standpipe...

Most don't....

I run flood and drain with weep holes.
I have a cap that screws onto the media guard.
The media guard has holes in it but they don't start until about 150mm down.
When I screw the cap on it creates a small siphon while the water is overflowing and the pump is on, (until it breaks at the holes in the media Guard).
So yes it works.
I like to think it creates a small 'tide' in the first 150mm of my growbed, kind of like waves lapping onto the shore of a river.