Ideas for Aquaponics Hybrid System Integration?

[Japan Aquaponics - アクアポニックス 日本]

Hi there,

I was wondering if anyone has experimented with hybrid aquaponics systems - specifically I am interested in the experience of anyone that has considered a system with:

• The fish tank at the highest point

• Gravity fed to one or more Grow beds

• Gravity fed to one or more DWC beds

• Return to the Fish tank via a sump

My real interest is in how people would have the water move from the media-filled grow bed to the DWC beds without a big drop in height of the system.  I am assuming that if the media-filled grow bed is being drained via a traditional siphon, then we are going to need quite a drop to allow for that - and that would mean that there would be quite a height difference between the media bed (and/or sump) and the DWC beds.

I am not sure if I have explained this very well - but if anyone has idea about how to integrate the media bed as efficiently as possible with a DWC bed, and ideally allowing the whole system to remain gravity fed... and can it be done without large height differences across the system?

I would love to hear people's ideas.

[RupertofOZ]

Just build a standard Chift Pist (Chop) media grow bed system... but configure the grow beds as constant flood rather than siphoned... ie. overflow the fish tank into the media beds... constant flood/drain by overflow.... into the DWC raft beds.... to the sump... then pump back to the fish tank....

With the combination of constant flood grow beds.. and the DWC rafts.... make sure you aerate the fish tank and/or sump... (as you have two growing components removing oxygen in the cycle)...

 

You could run a ChopII type configuration... retaining the siphons to drain the grow beds... which could drain to the sump... and supply the DWC rafts and fish tank from the sump pump (ala Chop II)....

I'd still oxygenate this configuration the same way though... (even though you might get some additional oxygen gain from the siphon return to the sump)...

[RupertofOZ]

Depending on your stocking densities, and not having played with Tilapia... you might need to experiment a little as to either what stocking levels are required... and/or what volume of grow beds, or additional filtration might be required before the DWC rafts...

But given the lower density nature of most people "friendlies" raft models... any external filtration needs before the rafts would probably be minimal... (if required at all)...and most would have something in place as part of the current raft configuration anyway...

 

I tend to think most people grossly overstock their media systems... in terms of both design, but more particularly in terms of nutrient production vs plant growth... and heck, it's really about the vegetable production anyway...

[Japan Aquaponics - アクアポニックス 日本]

Thanks again Rupert,  I have never used constant flood as I had assumed/read that there are issues with lack of oxygen at the root level - but the BYAP experiment seemed to indicate that it can be used quite successfully... that was a surprise to me.  In this case my earlier concern about constant flood has decreased, and so would make a simple hybrid system without big height differentials much more feasible. 

Are you supportive of the CHOPii system overall?  I have seen some fairly disparaging comments made on other forums... but could also understand the reasoning behind why they said it.  If particulate waste is increasingly made finer and finer (as suggested) then could this have more of a negative impact on the DWC system if it isn't captured in the media bed?

[RupertofOZ]

If you think about it .. there's not a lot of difference in running a media bed constantly flooded... and a DWC raft system... contantly flooded... the same caveat applies... oxygenation for the roots...

Indeed this is just as true for DWC hydroponics... or even NFT...

 

I'm not convinced as to the advantages of ChopII... but I'm not convinced as to the viewpoints of the detractors either... really, in the end, if the grow bed components, or stocking levels,  aren't sized correctly, then passing through the media beds, regardless of chop, or chop2... will ultimately result in the same situations...

 

But as one who has employed in-line filters in hydroponics, and in my "mega" hybrid NFT aquaponics system... and seeing as this is essentially employed currently in DWC systems.... then to my mind a simple standard Chop system, with perhaps some fine sediment settlement... would be probably better than ChopII

[Vlad Jovanovic]

..."My real interest is in how people would have the water move from the media-filled grow bed to the DWC beds without a big drop in height of the system.  I am assuming that if the media-filled grow bed is being drained via a traditional siphon, then we are going to need quite a drop to allow for that - and that would mean that there would be quite a height difference between the media bed (and/or sump) and the DWC beds"...

Japan, something like this may help your "height" situation with a flood and drain rig...

http://affnan-aquaponics.blogspot.com/2010/08/new-challenge-high-wa...

It seems as though this version of Affnan's design would significantly reduce the height of such a drop as you are concerned about. (That is if I'm understanding you correctly)...

[RupertofOZ]

The only real "height" difference you need between the grow beds and the raft system... is equivalent to the bottom of the grow bed and the inlet to the raft... in order to completely drain the grow bed... if using a siphon...

 

If you're using constant flood... the height can be even less... it's no biggie...

[Vlad Jovanovic]

Even better!

[Jonathan Kadish NYC AA Chair]

You can always put air stones in your constant flood media bed, they do this at Nelson & Pade.

[TCLynx]

It doesn't require a huge height difference between a siphon bed and a DWC bed for a siphon unless you think the height of the media bed is a huge difference.  You could basically have the bottom of the media bed be the same height as the DWC bed.

Most people do put air stones into their raft beds.  Putting them into a constant flood media bed probably isn't as effective since the air movement is going to be very restricted by the media and you won't be able to tell when the stone needs cleaning nor will it be easy to access for cleaning either.  Most people have found that as long as the incoming water to a constant flood media bed is well aerated and the flow rate fast enough to keep the bed from going anaerobic that the plants generally do quite well.

[Japan Aquaponics - アクアポニックス 日本]

Thanks TCLynx... can I ask though... if using flood and drain direct to a DWC - aren't there going to be problems with water flow?  I was thinking firstly that the blast from the siphon might be too much, and secondly that the flow will be only happen when the siphon kicks in, so a lot of the time there will be no water flowing into the DWC?  Is that ok?

I had imagined that if going with the siphon, you would need to add in a sump and then pump from the sump to the DWC (and/or back to the tank as well, as I believe Murrays new MediaFlo will do - i.e. CHOPii as Rupert pointed out).

Air stones I agree and have factored those in already.  I had wondered about their use in the media bed itself - could be interesting - I wonder if there is a way to do it efficiently and still allowing for their easy removal for cleaning?  Like TCLynx said though - wouldn't the air be quite restricted?  Surely easier to aerate it before it gets to the bed and then just make sure it flows through quickly?

[RupertofOZ]

You comment realting to flow to the DWC and siphons is correct.. but given most siphons activate pretty regularly... it probably isn't a major issue... but could be...

 

That's why I'd prefer to use a constant flow, constant flood to the media beds... which provides a constant flow to the DWC...

You'll still need a sump regardless... as you would with DWC alone... but a straight Chift Pist/Chop is all that's required...

[Japan Aquaponics - アクアポニックス 日本]

settled then .... constant flow, constant flood will be tried.  

Something I meant to ask... why don't people seem to use venturis so much?  Could venturi's be used on the connecting pipes between growbeds?  Has someone experimented with this?  I have just been thinking recently about how to get the maximum amount of passive aeration into a system in order to supplement usual methods.