Daisy Chain the siphon outlets?

[Jeff]

Hi guys and gals! Since I am still in the planning stages of my backyard aquaponics system, I am bouncing some ideas back and forth to make sure I have a functional and aesthetically pleasing setup!

I am trying to go over in my head the best way to set up THREE grow beds, horizonatally, with the fish tank on the far end.

That leads me to a question. Can I daisy chain the down spouts into a single PVC drainage pipe that will feed into the fish tank? Here is a crude drawing that I did to illustrate what I mean.



In my head, that makes sense, but without any knowledge in plumbing or suctioning, I have no idea if 1) this will still trigger the siphon, and 2) will the siphon still stop as it should?

Again, I don't see how this would NOT work, since the siphon should trigger and stop based on the levels within the grow beds.....but I need some opinions from you all!

[keith_r]

i'll probably be doing that myself..just make sure the main drain is large enough.. i'd probably go with a minimum of 3", but i already got my drain line.. 4"...might need 2 more fittings..

[Jeff]

i'll probably be doing that myself..just make sure the main drain is large enough.. i'd probably go with a minimum of 3", but i already got my drain line.. 4"...might need 2 more fittings..

I didn't even think about that. My drain pipe may be 3/4" coming from the bottom of the grow beds......and I was assuming that the main drain pipe that they would all connect to would be the same. But you're saying to make it larger (perhaps 3" or so).

[commander]

The collecting drain needs to be at 2" if you are dropping 3 3/4" siphons into it. You need to consider handling the flow if all three siphons cycle at the same time.

[davidstcldfl]

Jeff, it could work.....I tried to use a common header twice. Even after re-doing it the second time I wasn't happy....
The main issue is...the next bed to drain, seems to wait to start a siphon, till the one draining is finished
I finally ran a drain line for each bed....had the pipes running side by side in a neat fashion. I never had an issue with them after that.

If you try it....add a vent to the main header, before the grow beds/furthest point from the fish tank. (looking at your drawing....the vent would be to the far left end of the main header...before the 1st bed even drains into it)
I agree with Kieth and Commander...The bigger the header, the better....also use DWV fittings ....Drain/waste/vent...these fittings have long radius turns for better flow.

[Eleven11]

Looks good to me. Are you connecting the siphon output directly to the drain or making an opening in the drain that the siphon pipe will empty into?

I'd make sure the drain line is 3 to 4 inch in diameter and on a slight downward slope going into the fish tank.

I'd put a 45 degree elbow at the end of the drain line to reduce splashing and put a knee high stocking on the end for noise reduction and it will act as a filter and aerator.

[Jeff]

Looks good to me. Are you connecting the siphon output directly to the drain or making an opening in the drain that the siphon pipe will empty into?

I'm not sure I understand. What I was thinking was each siphon output would extend downward and insert vertically into the top of a T-Connector. The horizontal "sides" of the t-connector will have to be a 3-4" drain pipe, all leading back to the fish tank. Not sure that is possible, but I suppose it is (making a 3/4" output go into a 3-4" drain pipe.

I'd make sure the drain line is 3 to 4 inch in diameter and on a slight downward slope going into the fish tank.

Yes, I would try to have a slightly downward slope to help the process.

I'd put a 45 degree elbow at the end of the drain line to reduce splashing and put a knee high stocking on the end for noise reduction and it will act as a filter and aerator.

Since I got a high powered pump, I am also going to put a spray bar into the tank to help aerate the water. I never thought about a stocking for a filter.

[Jeff]

The collecting drain needs to be at 2" if you are dropping 3 3/4" siphons into it. You need to consider handling the flow if all three siphons cycle at the same time.

Is there a way to configure the system initially to drain in a certain order, and then leave it that way so that you always know that one will drain x-minutes after another? I was really hoping the one pipe connecting all three would be a good solution.

[commander]

I guess with a lot of work and some really fine tuning you could get your siphons more or less on a "schedule". Based on my experiements, I don't think that you could ever time it that precisely. However, if you construct your collection pipe out of 3" PVC and put T's where the 3/4" siphons drain into the collection pipe, you shouldn't have any trouble at all. The size of the collection pipe is more than adequate to handle all three at once. Having the 3/4" drains empty into the opening of a 3" diameter T should solve any problems with back pressure or flow affecting other siphon operations.

[bsfman]

Is there a way to configure the system initially to drain in a certain order, and then leave it that way so that you always know that one will drain x-minutes after another? I was really hoping the one pipe connecting all three would be a good solution.

If you use a big enough common drain (I'd suggest 4" drain pipe), you could run each individual grow bed drain into it. Basically, you'd be using the return pipe like a gutter and as such, it's not really necessary to plumb each drain into it with fittings. You're going to want at least one 90 degree elbow in each individual drain to help create enough hydraulic friction to start the siphons. Add a second elbow and very short extension and just insert the extension slightly into holes you've cut with a reciprocating saw into the drain/gutter. Cap the uphill end of the gutter pipe and angle it down to return to your sump through the open end. Even with all three siphons kicking at once, this should give you more than sufficient capacity to handle the return flow. I use something similar to this as a return gutter for my strawberry towers and it works quite nicely.

As far as timing the autosiphons to run sequentially - well, good luck with that! Very minute variations in the input line flow rates to each GB, slight variations in length of your standpipes, headspace variations in your bells, slight variations in the volume of media in each GB, variations in length and configuration of your siphon drains, and even rainfall will conspire to make each GB cycle in time of it's own particular choosing.