Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

The last couple of weeks have been really interesting in terms of reading up on some of the ideas and ideals of aquaponic systems, their designers, and in some cases, their rabid followers (shall I dare say worshippers?).  The Australian forums again supplied a bevy of examples of spats and howls around the mention of anything that does not resemble the purist form of media bed backyard AP – a fish tank and media filled beds.  Indeed, a heap of component suppliers sell these as their staple thus I assume that there is a great deal of passion (and money) invested in the premise that this is all you should ever need.  

 

By being a member of this group, you already behave ion a deviant manner.  Congratulations.  I have taken a particular interest in media beds, mineralisation and bacterial action of late.  There has been many triggers – seeing some 1 meter deep gravel beds in the IBC pdf, reading hateful exchanges related to suggestions that media beds cannot be plant anchors and mineralisation/ nitrification sites all at the same time, and finally, one of those “special” questions: Where, o where, did the new cast in stone, air tight, more important that the laws of Thermodynamics concept of “thou shalt make a media bed 12 inches deep or else” come from.  In both my and my wife’s post graduate studies we have seen similar things happen.  Someone, somewhere, makes a statement down the line of “12 inches seem to be a good depth” without trying to say it cannot be 10 or 50, and within a few short citations, the broken telephone of science, it becomes 12 inches or bust.

 

I’m not interested in going that way.  My beds are already too shallow. Sue me.  I’m taking an interest in multi-function structures.  Swirl filters that become mineralisation sites.  Floating media-filled sumps.  Deep drums filled with gravel (never to be cleaned again) becoming the first stage of a water source for a gravity fed NFT line.  I already have a gravel bed that is also a seed germination bed.

 

I think that there is way more room for these kind of thoughts than what is typically taking place.  Looking at Dr Lennard’s calculator, which I like very much for the components of AP taken into account, not necessarily the ratios recommended, there is always space being made for bio-filter size as a separate entity.  I’m going to push this concept a bit this season.  I’m planting my gravel beds, but I’m making a whole lot of media-filled structures that will never see a plant and adding them to the system.  With raised beds, I have the space for this, and I truly believe that the system can only benefit.

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I have some 55 gallon drums that are cut in half to make tow 18 inch deep buchets. I have filled tham with media and use them like large Dutch buckets. There is a constant trickle of system water going into the top and a drain at the bottom returning the water to the next lower trough. This method is working very well so far. My intention is to grow mainly tomatoes using commercial techniques. I have then planted with lots of stuff until the tomatoes get to a decent size. The corn has definitely responded well with the extra depth.
I intend taking a 150 liter drum, drop the "dity" water from the main pump line right to the bottom of the drum with a 40 mm pipe, then fill it with media almost to the top where the water will flow out into NFT pipes.  I don't know if I plan to plant anything in it, but I want to use some surplus pump capacity on the dirty water line for NFT.  I also want extra gravel volume for mineralization thus my current concept for a "deep" gravel bed doubling as a filter.
I like this quite a bit.  I have been so impressed with my one passion fruit vine in my home system that I am considering doing a whole lot of them if I can get some land to work on.  I can just picture a whole lot of drums along the side of a greenhouse all containing one passion fruit each.  It can even be a stand-alone AP system kind of resembling a dutch bucket system.  Fish tank, blue drums, sump, back to fish tank.
Interesting. The drains of the buckets I made go to my NFT and it is working better than I expected.
Kobus I agree whole heartedly with the Lets push the envelope concept. I am very very happy with my gravel beds being able to filter for rafts. My roots are clean and I really dont plant long term crops other that tomatoes in rafts and they are doing fine. I will state rafts are overrated for the hobbyist grower due to the limitations of what can be grown due to lack of root support. I am experimenting with corn as of late. They are 4 foot tall and do need some support help but love the rafts so far. I will on the next phase incorporate large gravel of 1in size in beds to 3/16 for seed beds like you are doing and then to a raft in next design. I absoulutly think a large commercial system can be designed with no degassing or mineralization for the rafts. I think with step down gravel sized right and enough volume of gravel it can keep the rafts water clean. I also think if you plant heavy fruiting crops like corn and squash in the gravel the system will clean itself. Of course worms and maybe nightcrawlers are a must. I am leaning toward constant flood but maybe they need to flood and drain to. I will also be feeding a fodder system off of the rafts clean water to see how that goes. That system will be on its own pump and timer. Being able to make a mixed system that is truely closed loop is really fascinating to me personally.

Hi Kobus,

Standing barrels are definitely a good idea for use with a sump and adds the extra bio filtration. You're so right, the AP conditioning is geared toward shallow 1 ft beds adding to expense of raising them for sump app. Also barrels are less costly and saves on construction time and labor with bed construction. What about the savings on space(sq.footage). It's ideal for a component sys. as you can isolate and service and reinstall quickly and easily with less down time by installing individual valves. A system with barrels in series will surely change the ratios of standard AP! 

You're so right there Harold - depending on the cost and ease of getting the barrels (as soon as a lot of people do this supply/demand issues are sure to push up prices) you can have a wonderful constant height system comprising fish tank, barrels and sump.  You can do cucumbers, tomatoes, fruit, all the larger items that would love having 100 kg of gravel all to themselves.  Dutch buckets on steriods!!!  We get those blue drums in all kinds of sizes thus you can experiment nicely. 

 
Harold Sukhbir said:

Hi Kobus,

Standing barrels are definitely a good idea for use with a sump and adds the extra bio filtration. You're so right, the AP conditioning is geared toward shallow 1 ft beds adding to expense of raising them for sump app. Also barrels are less costly and saves on construction time and labor with bed construction. What about the savings on space(sq.footage). It's ideal for a component sys. as you can isolate and service and reinstall quickly and easily with less down time by installing individual valves. A system with barrels in series will surely change the ratios of standard AP! 

After a few more days of head scratching, standing in my little "cube" and pondering multi-purpose components, I have come up with another solution for what I am doing.  Having started with an IBC tote as the FT and 4 raised media beds above water level as my initial "core" design, I am now filling in the spaces with multi-purpose stuff.  The first were sumps with floating media to add more water volume to the ever expanding unit.  Then came the sand bed and the different tower configurations.  I have written about the deep gravel barrel that I am planning to clarify surplus "dirty line" water for 50 plants worth of NFT.

 

Then my mind started wandering towards the lowest tier of the unit.  At the level of the fish tank and the sumps, I have gaps in the cube underneath my raised beds.  At first, I wasn't sure what I could do with these, but then my mind started floating towards a "growbed sump".  A bed at almost the same level as the sump, overflowing into it when water siphons from a grow bed overhead.  I intend to have 2 - 3 of these, made from 150 or 200 liter blue barrels cut down to size.  The bottom sections will always be wet, but the root zone of the plants will drain, making it a mix between a sump and a bed.  I will put tomatoes, cucumbers and all manner of trailing plant in here, and solve my space / light issues as well.  Having tall plants in the front beds don't work as the back beds suffer.  The one back bed has been taken over by a monster passion fruit, and in the other, I'm playing with sand............................

 

I'm sure these are in use already, but I think they will be valuable additions to my "complete basket" unit to be revealed somewhere between September and December. 

Hi Kobus,

With these new ratios, how mush fish would you now need? I know your feed has a higher than average protein but are you planning to supplement minerals as well?

Harold, at the moment, I plant to feed the 17 koi in there as much as they want to eat, and I'm expecting to move a few more over from the research system by summer.  I want to balance the system eventually without needing any supplementation at all.  Last summer, with all the plants going full bore, 37 tilapia was still too much - there was always ammonia between 1 and 2 mg/L left.  I think 20 medium size koi can run this unit, maybe 30 max.  My extra components are feeding my new philosophy towards mixed systems: Have almost as much media without plants in it as what you have media beds.  I'm going to expand on this theory in a mixed media blog soon, but the underlying principle here that I support is that a media bed full of plants does not do the same job as an empty one, even if you have worms in there.  Especially if you have perrenials. Thus, if you have the space, stick in unplanted media structures.  In the end, I will have a 120 liter swimming pool filter, a 200 liter barrer on its side (with around 180 liter capacity) and a 150 liter barrel filled with gravel doing mothing else than being bio-filter.  That is almost 500 liters of filter to a 1000 liter IBC. Then there is the four media beds up top, and the media towers.  These new sump beds will have a capity of around 80 liters of media but will support at most 2 plants, albeit larger stuff such as cucumber or tomato. I'll be blown away if I am able to record ammonia this summer.

 

This cube design must first optimize the nutrients going into it (40% protein tilapia feed) before I will up the stocking rate. I see it as a low density system built on four levels rather than a fancy HD unit.  I think HD is not for me any more. 

Harold Sukhbir said:

Hi Kobus,

With these new ratios, how mush fish would you now need? I know your feed has a higher than average protein but are you planning to supplement minerals as well?

Here is a latest little multi-use addition I'm working on.  Having decided to use the watercress bed for seed germination, I needed a new spot.  I decided to take the shade netting off the front of the system at the one sump, remove the sump lid and make a raft out of guttering to go onto the surface of the sump.  I must still put a float (polystyrene, foam or empty soda bottles) between the two gutters, and then it is ready to go in.  It will have enough gravel in the gutters to allow the plants to settle, but not sink the set-up below water level.

 

 

The holes in the base of the gutter allows water in, and there is sufficient movement in the sump (I am assuming) to let suffucient exchange take place.  The raft will also screen the floating media better, cutting on algal growth that has developed since I opened it up.

 

The conditions should be ideal for watercress.  Will keep you all posted on the progress.

Hi Kobus,

Great thinking as usual. You should get the "Emmy" for multiple components in a confined space, for sure.

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