Backyard Aquaponics
A place to discuss aquaponics

I'm setting up a CHOP system with 10 bluebarrel growbeds. Each growbed is equipped with an Affnan autosiphon, and the plan was to combine the outgoing pipes together through a couple of tees, as shown below.



I've never build a system with multiple grow beds before, so I'm a bit unsure if joining the output from several growbeds together like this will cause problems for the auto siphoning?

Has anyone done a similar design? If so, has there been any problems with the siphoning?

I run all my drains separately, much less trouble.

I think with all the piping connected you will have trouble breaking a siphon as it will have trouble getting air in to break.

I think you would have to redesign it so the siphons drain into an open pipe. Eg 20mm siphon/drain pipe into 90mm.

Will draw up a pic tomorrow to help explain

What are the problems you get? My problem is that the water is not going into a sump after this, but to a DWC, so it'll be PITA if I am to run separate pipes for each of the growbeds to the DWC.

Complete system below.

For a siphon to break it needs to be able to draw in air. From experience this comes from the bottom of the drain pipe. With all the drains connected it will be much more difficult for the siphons to get air.

Personally I would build a 90mm backbone with a 90mm T piece under each drain where I would then have the 20mm siphon/drain dump water into.

Hmmm... what if I just insert some tees on the exit (below the elbow coming down from the grow beds), with an opening pointing upwards so there'll be air from the top?

they'd overflow while the barrels fill..
i drain a few 1-1/4" drains into a common 4" drain with an air gap where the 1-1-/4 goes into the 4"

Agree with Arbe. This won't work - I have tried it and you get air locks that prevent the syphons from starting. Best to drain into an open pipe/channel.

If you put a riser breather tube at each end of the drain before the gbs it should allow air for siphon break.

Here is a quick pic of what I suggest.

If the pipe is above the water level of the DWC/Sump it wont overflow.

Sweet paint skills, Arbe!

Op- Yes you can do it like that, but as people have said simply make sure there is a place for air to get in near each GB drain.
So instead of joining each GB to the maindrain with T pieces, simply cut a slightly larger hole in the maindrain and have each syphon run into that - no seal around the pipes. So the same way as people would use uniseals for, but without the seals.

obviously making sure the maindrain can handle the flow of all siphons going at once.

An air gap for each individual siphon would certainly be best. I would probably use oversized tees, with a larger piece of PVC surrounding the siphon drain pipe, while leaving enough space for air to enter. Then, make sure that PVC manifold can handle all siphons kicking at the same time!

When my big system is built I will have blue barrels laying on their sides under my grow beds. These drums will be tied together and will dump into the main tank. The grow beds will dump into the blue barrels, this will give me more thermal mass for my green house, allow for more tanks to keep fry, minnows, prawn, etc, and be a easy way to dump my grow beds. I figure one between each two are three grow beds, but will make my final changes as I build.

That is a good idea helomech.