Backyard Aquaponics
A place to discuss aquaponics

I know this is not going to be popular, but the truth is that if you purge some water out of the system once in a while(dump some solids) and you have good bio filtration then the nitrate level will never be a problem with the fish in a single grow out season. The wicking system would work just fine and would not be for keeping the nitrates to 0. However, it is possible that nitrates might get so high that the plants only want to put on growth instead of fruiting, but not likely to happen with plants in the bio filter. With the wicking system veggies will grow better and produce more because a broader range of nutrients will be available. Food&Fish said he has 3 wicking beds with great success. Nitrate uptake would be limited to water uptake. The carbon material and the nitrate might also work with bacteria to breakdown compost and release more nutrients. in the soil.

Great read S'man!

Great pics of the little buggers too.

Cyara, no I'm not using coir as a wick. I'm using a "pump" made of an aquatic plant basket filled with potting mix (soil and compost) suspended into the water. This fits through an aeration bench which I am plastic welding into my barrel GB's. I'm dropping the standpipe to only flood to within say 50mm of this bench. The water will then be drawn up to the plants above it. Something like the image attached.

Thanks for that. I'll probably plant the basil on the "earthtainer" side then. For the gravel GB side I'm looking for plants that will thrive in very moist conditions. The mint doesn't really scare me off as I've battled it for 3 odd years and I know how to tame it (weedeater) Anyway, I'm working on a mint "witblits" a local (very strong) spirit that I'll be distilling soon so I'll need as much mint as I can produce.

I don't think it actually matters as the plants on that side will get most of their nutes from the soil/compost mix anyway. The gravel side (mint, watercress) will do most of the actual nutrient take-up in their existing gravel grow-beds (flood and drain)

Seems somewhat contradictory Dandi... if you've got good bio-filtration then solids shouldn't be a problem...

And nitrates have never been shown to be a problem unless above levels of 500+ for a significant period of time... and that's in RAS...

Given our AP systems are continually utilising nitrates... other than when a large percentage of the growbeds may be empty...

I just don't see a problem...


Why??... how??... from where... here,below???...


Unless used solely as a "satellite" system... I'd have some concerns about the possible introduction of soil/compost bourne disease into the fish tank...

Seems a desire to go back to a composted soil garden... with the addition of regular doses of urea... ammonia from the fish water...

What don't you guys believe in aquaponics anymore...

And such a system... just like a soil garden... with constant addition of nitrogen... is going to suffer the same "perceived".. or actual... problems mentioned with regard to leaf growth as opposed to fruit/flower/seed set anyway... unless you introduce Potassium at the right time/stage...

Normal soil based systems deplete nutrients, particularly trace elements... unless regularly supplemented... by fertilisers, compost etc..

And surely you'd suffer the same in a compost based wicking system... fed by filtered (solids removed) AP water...

And would they be more productive/area... than NFT... or a raft system... or even an autopot system...

Most wicking systems... are used for seedling propogation... not for grow out...

i.e the "Caplus" autopot cappiliary tables... http://www.autopot.com.au/content/docum ... s-pdfa.pdf

http://www.autopot.com.au/default.aspx? ... 8573d8e9df

Which are only an adaption of similar hydroponic tray methods... with supplementary heating...

And the same methods that orchid growers have used for years for propogation...

F&F uses a "wicking" system.... but with (from memory) unfiltered AP water... on a modified watering cycle... with inert, disease free media

And just a note on the "Growingpower" setup and figures.... and I'm not knocking them for what they do... or necessarily how they do it...

But the figures quoted for plant production... are from ALL their various growing methods.. hydroponic, vermiponic, and aquaponic...

An article by Rebbeca Pade... gives you a breakdown of the (then) 5 greenhouses and what/how things are grown in each...

http://www.growingpower.org/Aquaponic%20Journal.pdf

When written... 2004... only one greenhouse (#4) was actually an aquaponics system... with the #2 hydropinc greenhouse being conveted to aquaponics...

They may well have changed more to aquaponics, but there still seems to be an emphasis on other methods from what i can find published...

At the time the article was written... the aquaponics system stocked 800 Tilapia in a 4400gallon tank... for about 400-800lbs per growout... a low stocking density...

And the Tilapia were fed a diet of worms, duckweed and organic dog food..

Given the total area is quoted at the time was 12500 sq ft and has obviously been increased....



And predominantly grows watercress and salad greens... it's quite possible the annual yield figures are true...

But the figures aren't solely aquaponics systems yield... and in comparison to similar yield from hydroponic operations of the same size... and/or NFT add-on systems such as "Taylor Made"... and the now defunct "Barramundi Blue" ... Aren't really that exceptional...

SynaptoPump!

I did EarthTainers for tomatoes this year. (And straw bale, and lasagna and everything but the Topsy!)
Modified to use AP water, this can be a powerful system - but I have been trying to predict what method of irrigating would work best for different vegetables.
I might convert a few ETs while saving up for lightweight media and deep growbeds. The tomatoes are tired. External siphon is a possibility since the units are already built. I understand you plan on adding bench to straight standpipes and cont. flow?

I like that

Rupe,

From my very limited knowledge of fish health, my understanding is that fish pathogens are strictly waterbourne.

Please bear in mind that this "hybrid" system is very experimental at this stage and I am in no way knocking traditional AP techniques and I would never consider it for any of the various commercial systems that I have built until I have researched and tested it thoroughly. I am (as usual) just trying to "think outside the box".

Cheers

Why would this not be popular? Surely the objective here is to get optimal fish and veg growth out of a system whatever the means? Or am I missing something?

Nahh , you haven't missed too much Synapto ,, just an ongoing discussion as to whether solids should be removed pre- grow bed or allowed into grow beds and worms added.
I'm with Dan on this one ,, but hey , no-ones done a side by side comparison over a sufficient time period to really quantify the answer.

Rupe, what I was trying to communicate is that nitrates are not a problem in a system with some water exchange from time to time; even with no plants.

From what I gather about "growing power" compost is the primary method of growing and the fish water feeds this process. Their water cress and gravel is used to clean the water more than to produce a crop. I think the combination of AP and compost/soil growing has real merit and in the interest of food production deserves consideration. I agree with synaptoman on the veggie production in AP. It is satisfactory and I believe that it could be better.

No arguement from me DanDi... about nitrates "not" being a problem... regardless of whether or not there are plants....

Nor about GrowingPowers use of gravel beds and watercress being used to clean their water.... which they then fed to their compost beds...

Was merely trying to point out their methodology is exactly that... and not a traditional "flood & drain" or "continuous flow" media based aquaponics system... but more a "satellite" style of growing... essentially using a "soil" media.... and I believe a degree of run to waste...

Such a combination is also utilised by Taylor Made here in Australia... with pre-filtered, solids removal feeding NFT... which is then remixed with the solids and irrigated to outside "soil" beds...