averan

An alternative to auto-siphons, the E-Siphon

66 posts in this topic

I've been working for some time now to come up with an affordable alternative to auto siphons. They may be fine for the home garden where you can fiddle with them and check daily, but in a commercial system (i.e. lots of media beds!) I want something more reliable and with more control.

One of the other issues that I've dealt with is the heating/cooling effect of flood and drain beds. I manually alter my system by pulling out the siphons during the winter and turning my beds into either constant flood or wicking mode in order to minimize heat loss. If the sun is out, my greenhoused beds can actually pick up quite a bit of heat, so during the winter I can effectively heat up my water by turning the siphons on only during the day. Obviously this is really tedious to do by hand twice a day and I'd love some sort of method to automate this whole process.

The ultimate level of control is to have a custom valve in each bed that is electronically controlled by a common irrigation timer. Each bed would be a zone and you can totally customize the flood and drain times for each. I'm still working on a prototype of this, but alternatively, I found some ready-made parts that are a bit too expensive to use on each bed, but that could be used to control a group of beds as a zone.

For this to work, each bed needs 2 drains: one is just a hole at the bottom for when you want to drain the bed, the other is a stand pipe for when you want to flood. By opening or closing the outlets with an electronically-controlled valve you can decide when to flood and when to drain. Connect this up to one of the new wifi connected irrigation timers and you can automate or adjust it all remotely on your phone/computer! While this particular approach uses currently available parts, it does require more plumbing and a second drain taking up space in each bed.....something I'm not entirely happy with.

The valve + actuator costs $120. Obviously too expensive to have one for every bed.

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Edited by averan (see edit history)
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And here are some photos of the test prototype valve for control over individual beds.

Basically, there is a larger movable stand pipe around the inner stand pipe. The inner stand pipe has slots cut into the bottom such that it's not functionally a stand pipe anymore, but rather a way to mount the servo up high above the water. The servo connects to the outer pipe sleeve by a short rigid wire (not shown) and raises the outer stand pipe to let water drain out at the bottom or lowers it to close and flood the bed.

I discovered that a 1.5" coupler fits nicely inside 2" pipe, and then a piece of 1.5" pvc inside the coupler fits perfectly around a 1" stand pipe. I used ABS for the outer sleeve because it is much lighter than PVC making it easier for a small servo to lift.

What I'm missing still is a small electronic circuit to control the servo/valve that interfaces with the 24V supplied by a common irrigation timer. I have found some schematics to create one and the parts would only cost about $5. I think I could make these for $15-20 in parts, which would not be too bad for putting one in every bed. If I can get this working then I will have total control over the flood and drain cycles on individual beds! That means I can better regulate heat gain/loss and fine tune cycles for different crops.

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Hi Averan,

 

I have a couple of questions:

 

1. Given the relative simplicity of sub-surface continuous flow grow beds......and that there's virtually no difference in plant growth....why bother with auto-syphons at all?

 

2.  If you're planning a commercial operation, what is your rationale for using media beds.....given that no one else does?  UVI tested them in the late 1970's and found them to be impractical for commercial purposes.

 

By the way, kudos for your attempts to innovate.

 

Gary

Edited by GaryD (see edit history)
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1. I'm not actually bothering with auto-siphons, but rather with media beds that can operate in any mode I want (flood&drain, wicking, constant flood). The benefits are: more bio-filtration, zones for mineralization and anaerobic disgestion, more options in media wetness for different crops, space for longer-term crops to grow out, maximize nutrient extraction from fish poo.

2. incorrect. Nelson and Pade along with Green Acre are two good examples of people using hybrid commercial systems. There is a use for grow space for cut-and-come-again crops like tomatoes, peppers, melons, etc. And there are good reasons for diversifying your crops. My commercial systems are hybrids, using DWC for fast-growing greens where the entire plant is harvested, and Media Beds for longer-term crops where the fruit or leaves are continuously harvested or for root crops.

 

Thanks! =)

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Hi Averan,

 

 

The benefits are: more bio-filtration, zones for mineralization and anaerobic disgestion, more options in media wetness for different crops, space for longer-term crops to grow out, maximize nutrient extraction from fish poo. 

 

Most of those things will be catered for by the dedicated mechanical and biological filtration that is a feature of any good system design.

 

2. incorrect. Nelson and Pade along with Green Acre are two good examples of people using hybrid commercial systems. There is a use for grow space for cut-and-come-again crops like tomatoes, peppers, melons, etc. And there are good reasons for diversifying your crops. My commercial systems are hybrids, using DWC for fast-growing greens where the entire plant is harvested, and Media Beds for longer-term crops where the fruit or leaves are continuously harvested or for root crops.

 

Green Acre are a low density aquaponics system and, as has been canvassed at considerable length on this forum, such systems can't compare with hydroponics systems of similar size and configuration.  Green Acres is also supported by income other than that derived of growing plants......like all of the Friendly Aquaponics clones......so they're not a good example of what's viable in commercial aquaponics.  Coupled with that, the last time I checked, I got the impression that they had abandoned the infamous CHOP2/Flomedia design that they had got from Murray Hallam.

 

While Nelson and Pade may be offering a hybrid system option, I'm always guided by what someone would set up for themselves rather than what they'd sell to someone else......and I seriously doubt that they would set up a system without dedicated mechanical and biological filtration.

 

All of the "cut again" crops that you mentioned (and more) are able to be grown in a DWC raft system - as evidenced by the experience of UVI, Savidov and others.

 

Feel free to tell us more about your commercial system.  I'm happy to be persuaded otherwise, but other more experienced aquaponicists have trialled and rejected media grow beds for commercial use on the grounds of them being too labour intensive. If they are being used as the sole means of solids capture and bio-filtration for raft systems then the design is really flawed.

 

The only long term successful commercial approach is where the system is set up as a recirculating aquaculture system......with growing systems attached.

 

Gary

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Thanks for your input Gary, but it is a bit off-topic. I'm not going to argue about whether or not my concept for commercial aquaponics is viable, or appropriate for you or someone else. I am only interested in this post about discussing alternatives to auto-siphons and the benefits of having precise automated control over flood and drain cycles.

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I'm just wondering instead of trying to control the draining of the bed, you could control the input.  A series of solenoids with output pipes to the grow beds might offer more reliable control. Such as  the way hydraulic presses operate to send hydraulic fluid to actuate what is needed.  The solenoids would just be used with water instead of hydraulic fluid. I haven't been over the designs in 20 years, but wondered if you had considered that route.   A single pump could be used to sequentially fill multiple beds with a timing circuit controlling the whole mechanism.

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I would have less control over the beds. It is not just about cycle timing. With only the inlet controlled I could never switch between constant flood/wicking and drained. Also, solenoids are not an option due to their pressure requirements and small orifice prone to clogging. I am fully aware of the existence and use of low pressure sequential valves, but they don't give me the functionality I seek.

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The irrigation valve won't work under low pressure. Other valve also leak or clog due to solid & bio-slim. To switch between siphon and constant flood, you can just simply use an air valve on the bell to break the siphoning effect.

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Hi Averan,

 

Thanks for your input Gary, but it is a bit off-topic. I'm not going to argue about whether or not my concept for commercial aquaponics is viable, or appropriate for you or someone else. I am only interested in this post about discussing alternatives to auto-siphons and the benefits of having precise automated control over flood and drain cycles.

 

 

I had no idea that we were arguing......and I was responding to comments that you made.

 

Chill.

 

Gary

Edited by GaryD (see edit history)
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Thanks for your input Gary, but it is a bit off-topic. I'm not going to argue about whether or not my concept for commercial aquaponics is viable, or appropriate for you or someone else. I am only interested in this post about discussing alternatives to auto-siphons and the benefits of having precise automated control over flood and drain cycles.

 

Use high and low water level sensors to activate motorized valves controlled through a PLC...

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Earthan has it

Normal irrigation stuff has really poor reliability and requires pressure to operate, often burns up considerable head too.

Bioslime will clog even the most rugged of these types, they usually have fine, like 2-3mm orifices inside.

You can buy low pressure changeover valves but again not that reliable, only need one for a number of beds though.

 

Can use pneumatic actuation which works out way cheaper than motorized valves Im used to and more reliable. But your in a whole new league of investment if your considering either of these options seriously.

There are some irrigation controllers used for misting or climate control which are up for this kind of duty but not cheap and PLC can be made to do the same things - programming is what costs.

Not many irrigation controllers can take multiple inputs.

Control wiring is a headache in greenhouses and nurseries.

 

For what its worth I have 5 auto siphons which havent faltered in 4 years continued running, not a big sample but good success rate.

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Ok, just an experienced point of view, I design and specify greenhouse irrigation systems professionally and spend long hours fixing old ones.

Those actuators wont handle running on AP water for long, and if your coupling them with those valves then Ill bet you will need pressure to make it work.

Cheap irrigation controllers only work on time and have limits on how many cycles you can program per day, most common types have just one input to pause the whole operation - rain switch

You could use a simple cycle timer if thats all you want.

Wiring is very different to plumbing as it is effected by UV and water (and insects, fertiliser, lightning, etcetcetc) Its also very expensive and trouble shooting difficult.

 

I guess you will work all this out over time that it IS all about reliability.

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That valve is motorized and operates with zero pressure. The actuator doesn't actually touch the water so I don't understand how it matters what 'type' of water you use? Yes, most timers can't do hourly cycles, but I think this one just might:http://www.bluespray.net/index.html

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I was googling trying to find a solution for developing my system and came across this discussion.  Wondering if there has been any updates, and what folks ended up using.

 

Like the discussion above, I don't want to rely on bell siphons. I would like low pressure valves, one for each of my 4 grow beds to let water in sequentially (when one bed is full it shuts off, then the other one fills, etc).  Then I want an additional 4 valves that release the water from the beds sequentially.  I have been trying to find controllers, and valves, and have not had a whole lot of luck.  The controller would have to turn on once per hour (or so), 8 different stations for a user specified time frame.  I don't know if something like that exists - or whether I am taking the wrong approach.

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If you going with media beds, I would strongly urge you to consider subsurface flow, ie water is ran from about mid depth of the grow bed, up to a few inches below the surface depending on the wicking ability of the media.   No siphons or valves to clog up , water level remains more consistent, can be expanded to many times depending on pump capacity. 

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That's what I call 'winter wicking' mode. ;) Reduces heat loss too when the air is cold but the sun is shining.

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Eschmidt, no, I gave up and switched to wicking beds and nft pipes. I miss my gravel-only beds sometimes, but I've learned a lot from my latest experiments and enjoy not worrying about siphons!

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Thanks for your replies!

i was thinking of using 3/4 granite, which I would guess has very little wicking ability.. Before any water goes in to the media bed it is going through a clarifier, demineralization, and probably a biochar filter I am going to make. The water will not travel directly from the fish tank to the media beds. Everything goes to the sump, first.

So what you guys are suggesting is sort of a modified wicking bed... Not using compost or soil like a dead end wicking bed that is not part of the loop.. But a material that is non organic and has wicking properties and can be part of the system? Reason I want some sort of media bed is for the larger fruiting veggies. I am also going to have rafts, and had been thinking of a traditional off the loop wicking bed for root crops.

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i use 3/16" cinder as my preferred medium. you can pour a 6" layer of gravel on the bottom, then cover the top 6" with small cinder.

 

the cinder wicks very well and is much easier to dig around in.

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To switch between siphon and constant flood, you can just simply use an air valve on the bell to break the siphoning effect.

 

Or just remove the bell... ;)

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What I mean is automation not removing the bell by hand. Using air valve instead water valve will avoid clogging.

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That's the basis of the prototype that I mocked up. It just needs someone to custom fabricate the valve and put together the control system.

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