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27 Days Growth in Floating Raft Aquaponics

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Hi,

I have seen recently people posting sensational plant growth on aquaponic systems in short periods of time. What I found interesting is we have difficulty replicating the healthy growth....

The following two photos represent an aquaponic system with integrated gravel bed, wicking bed and Floating raft.

The Floating Raft in these photos show a variety of leafy greens planted as seedlings on 28th of March 2012

The second photo shows the growth as at 23rd April 2012. A total of 26 days.

The system has 300 Jade perch feeding 120 grams and 30 Silver Perch over 500 grams feeding an additional 100 grams. Total feed applied per day is 220 grams.

10 days ago the system was showing signs of nutrient deficiencies throughout both the gravel bed (now two years old) and the floating raft. The wicking bed has matched the growth in both gravel and floating but has no deficiencies (show you later)... but not as densely planted

No other nutrients have been added to this system during this grow period.

What is interesting is this system is over 2 years old now and new plants put in the system show a lack of complete nutrients to grow healthy plants. They are a little tightly packed in the raft...

Anyone have any suggestions how to correct this?

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Edited by Earthan Group (see edit history)

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Hi again!

Below is two images taken of the gravel bed with the same time as the floating raft pics above.

This is showing the growth of Basil and Tomatoes. Seems some got taken out by something.....

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Here is the wicking bed. The bed gets the least amount of light compared to the other two and is not as densely planted as the floating raft.

It looks a little sparse but it has some small chives and some fenel from memory which makes it look that way.

But... the plants are exceptionally healthy and no bugs at all. The floating raft got smashed earlier on by bugs until the nutrient deficiencies were corrected late last week.

I guess you are what you eat comes to play here.

Interesting just the same.

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Let us not forget that same set up did the following with 120kg of fish in it..... but lettuce and tomatoes are easy peeesy to grow...

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would it be possible to to get a close up picture of the leaves showing signs of deficiency?

the raft spacing looks fine... the only problem i would see with it would be competition for sunlight as the lettuce gets older depending on the type/s of lettuce you planted.

from the distance in which the picture is taken from, the raft system looks like it's either missing iron, or is going through oxygen deprivation... i can see that there is a hose running along the left side of the raft tanks... is that an air hose to put air diffusers into the water? if you are oxygenating your water in the troughs then i would guess iron, but again, without seeing what the veins of the leaves look like up close it's hard to tell what's going on... the reason why im guessing iron def. is that the bases of the leaves still have some of the green pigment but the upper edges look like they're fading... this is a sign of manganese def. or iron def, but iron is the more probable of the two.

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Any way to get nitrate, carbonate and ph readings?

Your filtration may be a little too effective for the plant system.

I generally find I have to supplement magnesium,calcium, potassium and iron. Phosphorus seems to normally run high compared to the nitrogen output of the fish effluent and can cause calcium precipitation.

Of course, this is why I find your Earthan beds so intriguing, it appears to overcome or diminish this problem.

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from the distance in which the picture is taken from, the raft system looks like it's either missing iron, or is going through oxygen deprivation... i can see that there is a hose running along the left side of the raft tanks... is that an air hose to put air diffusers into the water?

I agree with you Damon, and we added Iron last week which they started to recover, though the corriander and the bok choy did not at all.

Any way to get nitrate, carbonate and ph readings?

All the readings are fine and we have some more tests coming back next week so will let you know how that goes.

Your filtration may be a little too effective for the plant system.

Yeah we thought about that but considering the feed load and that we mineralise the solids and re-introduce them through the gravel bed, then to the raft (sound familiar? Flow..dia...) So there are plenty of goodies coming from the fish system.

Of course, this is why I find your Earthan beds so intriguing, it appears to overcome or diminish this problem.

Yes we have not had any issues with the Earthan Beds. That particular soil bed does not work like our Earthan Beds but primarily a Wicking Bed but it does well on the AP water.

That is why we looked into the Earthan Beds a little more or I should say that is why we seem to only build systems with Earthan Beds. The design has come a long way to where there is no gravel in the system at all. Much easier to work with...

Anyway. All this talk about Aquaponics being "organic" and adding all of these other fertilizers like seasol, maxcrop (or what ever it is called), calcium, iron, potassium and the like pushed me to look for an alternate way to actually grow organically.... Getting closer I think.

If by chance you are trying to replicate someone elses huge perfect lettuce growth to impress others, can I suggest you go to your nearest hydro grower or farmers market, buy yourself a couple of trays of his produce, (which will come complete with roots intact), plug them into your growbeds, rafts etc, photograph them or better still film them on your little handy cam and distribute the video with you gushing about the your wonderful achievment.

Funny you should say that Jan. I watched a video this morning of raft lettuce and they were perfect! Really well done! Not a mark, no insect marks in an open grow dome, well formed and exactly the same size. What I found interesting is the root of the lettuce where bleach white and be damned if I can replicate that with the tannin (brown tea) in aquaponic water. Nor have I been able to grow every lettuce perfect...

Whats more is as soon as we see deficiencies in the plants, the insects take over. Take a look at the plants in the front of the the image below and the color of the roots in this raft aquaponic grown tomato.

Does anyone else have really clean bleach white roots in their floating raft?

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In stark contrast to the video I saw this morning with perfect lettuce here is a video with Myles Harston of Aquaranch.

This is the bio from The Aquaponics Ass. conference:

Tips for Profitable Commercial Aquaponic Growing – Myles will be sharing what he has learned from his 26 years in commercial aquaponics and aquaculture. He will be especially focused on his experience in how to make a commercial aquaponics venture successful and profitable.

Myles is the founder of AquaRanch, the first commercial aquaponics farm to grow tilapia from spawn to fillet and organic produce from seed to retail. Myles has been involved in aquaculture since 1985 and aquaponics since before it was even called aquaponics.

This is a write up on the project near completion by the Pades:

http://aquaponicsjournal.com/docs/articles/AquaRanch-Aquaponics-Greenhouse-Nears-Completion.pdf

And here is the video. While the sound is not great and there is a blower whistle it gives you a pretty good idea what a commercial aquaponics set up would look like along with the produce grown. Not sure the produce looks that perfect. Not that there is anything wrong with that, but from a guy with decades of experience (not five minutes and a video camera) the comparison of the growth compared to what I saw this morning speak volumes...

If I was in America, I would be looking to spend a few weeks with this fella.... not 4 days with ....

Enjoy!

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Just trying to eliminate possibilities here... but the rippling effect that I'm seeing in your trough where you have sections of goo growth in between areas of poor growth reminds me of something I've seen before... do u have any oxygen inputs in your troughs? I don't know why low d.o. in the troughs cause the rippling but once we added air stones to the system we had congruent growth across the board. If you have a small aquarium air pump you could plop an air stone or two in the trough underneath the sections of poor growth and if nothing changes its not the air... that is unless you have a d.o. meter handy to test the d.o. in the areas of poor growth. On the CAP we added 5 6" air stones to each 80 ft trough... the average d.o. of the system was a little over 7 ppm which is a bit of overkill, but the lettuce growth with the elevated d.o. levels were fantastic.

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Just trying to eliminate possibilities here... but the rippling effect that I'm seeing in your trough where you have sections of goo growth in between areas of poor growth reminds me of something I've seen before... do u have any oxygen inputs in your troughs?

Hi Damon,

I forgot to answer your first question. The hose you see running the length of the grow bed supplies 60 liters per minute through an air tube the entire length of the trough. The problem is not oxygen. Keep in mind there is a variety of greens in that trough (about 12 different types). The poor section is where the plants got smashed by bugs.

I am expecting a full range of tests to be returned to me today or early next week. That will give me a better indication of what was happening.

Regards

Paul

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Anyone have any suggestions how to correct this?

post-5185-13795789687235_thumb.jpg

Cheers

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I am expecting a full range of tests to be returned to me today or early next week. That will give me a better indication of what was happening

As promised here are the results of the last test.

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Most of these are below good growth for lettuce and much too low for tomato growth. Which is odd because we can grow tommys, as we have shown, however discussions with hydo experts that have tried tommys in aquaponics say, they grow well in a media but the plants do not produce as much fruit as hydro...

You can see the Iron is somewhat ordinary and anything reading <0.005 could mean it is basically not there at all because the test reporting level was at that point and would not read any lower.

Keep in mind this is a well mature system runnning for over two years in which you would expect to see the mineralization of solids producing a higher level of nutrient in the system, but is simply does not.

Also, this system was without plants for 6 weeks prior to the planting and tests where taken 2 weeks after planting.

Expensive to do these tests and I post it for you guys free. The reality is, there is a mountain of speculation on aquaponics and very little facts. Most of the facts have been distorted to suit who ever is selling that information. Majority of the information lacks any science and lots of "I feel and it is just great" and perpetual rubbish.

I suppose providing some scientific answers to some of the bull**** out there is why I post this for free.

Regards

Paul

Edited by Earthan Group (see edit history)

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Low on Iron, and Sodium build up as I see correctly.

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Low on Iron, and Sodium build up as I see correctly.

True. The salt build up was applied a few weeks prior to the test. Still at relatively low levels. I should have noted the results were in ppm (mg/L).

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going with the fact that your system has been up and running for 2 years, im assuming you've had growth over those 2 years... wouldn't different types of fish feed shift some of those readings depending on what's in it?

just spitballing here... but what's on the contents label of your fish food? if it's not too much trouble... given the base amount of iron per serving size in the fish food, increasing it should raised the levels in the water... also things like preservatives to elongate shelf life could have some detrimental effects in the water.

i've seen some phenomenal growth come out of dwc systems. i've even got it recorded... im just trying to find/ eliminate options or find correlations with the problem...

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Phenomenal growth in comparison to commercial hydro?

The history of growth in the system is a good point.

Previous to this change in stock, it was running on average 1.2kg per day of 32% protein. Harvested 100 kg and restocked with fingerlings. They run at 220 grams per day of 45% protein which is not adequate to provide nutrient for the 18m2 (190 odd square foot).

I was under the impression that having a media bed mineralising wastes produced a broarder spectrum of nutrient. While there is some nutrient there in that report, I doubt it is enough because as soon as we dropped the fish feed volume per day, the system crashed, even without planting it for 6 weeks and still feeding the fish. With the amount of feed going in it every day, day after day I would have thought there would have been a good build up of nutrient in the gravel bed.

Even prior to the water test, we had an ammonia spike which is odd because we reduced the feed, but that was related to alkalinity even though I thought the gravel beds was feeding back into the system.

The total nitrogen in the system is a little low but good enough for leafy growth and it stands that ammonia is being produced by the break down of the solids in the media bed, however the nutrient profile is not what we expected.

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Expensive to do these tests and I post it for you guys free. The reality is, there is a mountain of speculation on aquaponics and very little facts. Most of the facts have been distorted to suit who ever is selling that information. Majority of the information lacks any science and lots of "I feel and it is just great" and perpetual rubbish.

I suppose providing some scientific answers to some of the bull**** out there is why I post this for free.

Regards

Paul

Thank you Paul for sharing.

I'm new in AP, but this is so obvious. That is why I leaning to soil GB in AP or vermiponics or both. Gravel beds stay the same as basic of AP system, but toped with soil.

I can't say it is like your Earthan bed because I don't know how it works ( design ), but I gonna do it my way.

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That is why I leaning to soil GB in AP or vermiponics or both

And fish also. So 3 systems in one or separately.

Caca

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it's making sense... although some people have had progress with some fruiting plants in the system, leafy greens of jut about every time have done well, even in FAPs lightly stocked systems.

what's the brand of fish food that you're using? i want to compare it to the Rangen brand which is what FAP used.. compare it's total composition.

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Very close to the results posted a few years back by another member on the board. He was using test kits instead of sending to a lab. He starts posting tests about page 6 of this thread

Nice to have an independent lab verify. Thanks for the post.

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Thanks for providing the numbers. I know how expensive water labs are. I've got a master test kit that does things like phosphorous and iron. I'll post my numbers if I ever get around to using it.

I don't know enough about hydroponics to really provide any non-speculative insight into the data. If that was a drinking water sample, the salt would start to be getting into the noticeably unpleasant level.

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Hi Paul,

I'm not well enough versed in nutrient analysis to be able to make definitive judgments about your water tests but I offer the following for consideration:

  • Your tests tell you what is in the water - but not in the growing mix in the wicking bed.
  • The wicking bed will function more like a conventional soil-based garden in that some of the nutrients that it needs will come from the growing mix (and will be replenished by the breakdown of the organics in the bed).
  • Given the above, is it possible that the raft system is deficient in iron where the wicking bed is not.
  • Is there something about raft culture which reacts badly to higher salt levels?
  • If you have two growing systems that are working well.....and one raft system which is not.....is it possible that the combination is not working out for the raft system? I'm thinking particularly of the wicking bed. Is it possible that the mulch is absorbing the nutrients?
  • While those nutrients become available to the wicking bed as the mulch breaks down, the breaking down process (most of which will occur above the water level) may deny them to the raft system.

Once you address the iron deficiency.....and any salt issue....are you able to isolate the raft tank and run that on its own?

Gary

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Hi,

By the way, contrary to some suggestsions, raft systems will grow fruiting plants just as readily as other growing systems. UVI grow tomatoes, peppers and okra for years.

Dr Nick Savidov specialises in the use of raft systems for commercial production of tomatoes.

Gary

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