vkn

Our experiments with IAVS..

831 posts in this topic

VKN,

I completely agree, must know what the tote had been used for prior to growing food!

What are you the containers you have constructed of?

Regarding my system, I have gotten some flow issues fixed, so now my (2) 3' x 16' beds are getting good furrow flooding. I will be posting a time lapse video at some point during the Christmas holiday. Just got some more seeds in the sand, so looking forward to getting everything filled out and growing!!

More to come.....mh

Okay, great!  Can you elaborate a bit?  I'm just curious to know what issues you had with the flow.  I recall you have a sump.  Is that gravity flow from the fish tank to grow beds and timed pumping from the sump?  Or, are you using two pumps?

 

Those are Easy (educational aquaponics) systems made of FRP (fibre-reinforced plastic).  I came to know they are quite safe and durable.

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After several unforeseen delays, we got our sand media finalized at Turquoise commercial Aquaponics project. It is now being added to the iAVs grow beds.

 

Hopefully in a week or so, we would add fish and plants and get the operations up and running.

 

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Excellent news, VKN.

 

What is the particle size range of the sand?

 

Gary

Merry Christmas, Gary.

In brief,

No clay content, it is crushed granite.

<7% silt less than 200 microns.

Bulk of volume, about 60%, is 1000-1500 microns. Mostly crystalline.

Good pour volume.

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Hi,

 

The particle size and sand that is free of clay or silt is central to the efficacy of iAVs.  

 

The preferred sand specification is spelled out very explicitly in this article.....and in the graphic below.

 

On the matter of 7% silt, Mark offers the following.....

 

If sand with 7% silt by volume has an initial composite pore volume of 25%, and that sand is repeatedly flooded and drained, over time the silt will occupy the pore volume space of the lowest fraction of the vertical column.

 

Silt WILL fill in pore spaces, increasingly inhibiting drainage, leading to anaerobic conditions in the lower 1/3 of the filter, and cause turbidity in the tank water and probably irritate (if not damage) the gills of your fish (especially if sharp crushed granite particles - even (especially) if microscopic in size.

  • a sand bed of 1 m x 1 m x 0.35 m deep = 0.35 cu. m
  • a pore volume of 25% of the 0.35 cu m = 0.0875 cu m is pore volume
  • 7% as silt of the 0.35 cu m total volume = 0.0245 cu m of silt per 0.35 cu m of initial sand volume.
  • this is enough silt to 100% occupy (block) the pore volume of the lowest 28% of the vertical column.
  • Meaning, that over time,  the bottom approximately 100 cm of filter depth will become 100% blocked.
  • Assuming you could somehow 'manage' to keep the silt out of the fish tank and their gill structures.

 

 

 

Gary

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Hi,

 

The particle size and sand that is free of clay or silt is central to the efficacy of iAVs.  

 

The preferred sand specification is spelled out very explicitly in this article.....and in the graphic below.

 

On the matter of 7% silt, Mark offers the following.....

 

 

Gary

 

Thanks so much for the kind attention of Dr. McMurtry.  I appreciate all your thoughts on this.

 

I am very sorry for that confusion, Gary.  There is no much visible silt or powdery dust in the sand we selected.  We do not know the exact percentage of silt though.  By "<7% silt less than 200 microns." I meant, all particles that are less than 200 microns not alone the dust.

 

We have tested close to 17 samples of sand and this is so far the best we could get from here.  Though the sand were air-washed, we notice some discoloration in the first drain due to those dust.  We intend to run the water flow testing for 2 more days and then to remove all discolored water and to start again with fresh water.

 

Attached herewith are some pictures of today's first water flow event.  It took some time to soak up the water by the dry sand beds but we could see good drains by the evening.  It looks like they are working much better than my previous trials at Nanniode with river sand.

 

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Thank you for the information and I greatly appreciate you taking the time to steer us in the right direction.
 
I understand that where sand is used, particle-size distribution is an important consideration in order to maintain a good balance between drainage (aeration) and nutrient and water retention.  As I mentioned, this is what the best sand we could get after several weeks of searching around and testing.
 
Let me try to answer your questions first.
 
How do you know (determine) that <7% is <200 micron (0.20 mm)?
[vkn]Sorry I had overlooked the actual numbers.  Please find attached the sieve analysis report I got it today from the sand mining factory for confirmation.  The <7% I mentioned is of <150 micron (not <200 micron).  
 
Have you determined the actual clay/slit fraction (fraction less than 75 micron, 0.075 mm)?
[vkn] No clay was present but we could see some loose dust.  Silt fraction should be less than 1.5% as per the input given by the sand source.
 
Do you know the initial pore volume (prior to flooding/settling)?
[vkn] Initial Pour-space volume is about 40% +/- 5%
 
Do you know how much the pore volume reduces with repeated flooding/draining?
[vkn] With repeated flooding/draining, the pour volume reduced to 30% +/- 5%
 
Do you know the water retention capacity (hydrostatically bound, both prior to and following repeated flooding)?
[vkn] I found the water holding capacity about 5-10% initially but reduced to 2-5% or it should be even less following repeated flooding.
 
Do you know the initial hydraulic conductivity (HC)?
[vkn]  The initial HC was about 1.1 cm/s. 
 
Have you assessed how much HC will reduce with (after) settling (following repeated F&D cycles)?
[vkn] After settling the HC was static at 0.69 cm/s.
 
Appreciate any feedback you have on the above findings.
 
The sand placed in the beds were air-washed at the factory but not water washed.  The initial turbidity is, maybe, due to the erosion of fines/dust as you rightly pointed out.  There were no sand grains coming out.  After several flushes, water is now very clear.  We will run it for another day and then will get ready for the fish with fresh water in the culture tanks.
 
I am sorry if I had misinterpreted any technical terms being used.  I look forward to more stuff from you doctor.  Thanks again.

 

PS: On last question, I will answer in a separate post.

 

Attachment: Sand data from the mining factory.

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Are you intending to inoculate your filters with nitrifying bacteria and/or other micro-organisms?   If not, how do you intend to (so-called) 'cycle' your system(s)?

 

We intend to keep it very simple.  Add the first batch of young fingerlings between 5 to 10 g in weight in the large body of two culture tanks.  Add a small batch of plants in small segments of the respective two modules of sand beds.  We have divided the total number of sand beds into 6 such modules.  Feed the fish at a reduced rate which will be gradually increased in direct proportion to plant growth and the water quality factors.  Once things are normalized, incrementally increase the plant population based on the feed input.

 

Dr. McMurtry, what else should we take care?

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remarks in red text

 

Have you determined the actual clay/slit fraction (fraction less than 75 micron, 0.075 mm)?
[vkn] No clay was present but we could see some loose dust.  Silt fraction should be less than 1.5% as per the input given by the sand source.
 
On what do you base your silt fraction estimate?
 
Do you know the initial pore volume (prior to flooding/settling)?
[vkn] Initial Pour-space volume is about 40% +/- 5%
 
Do you know how much the pore volume reduces with repeated flooding/draining?
[vkn] With repeated flooding/draining, the pour volume reduced to 30% +/- 5%
 
about what I'd expect - sufficient if it remains this way throughout the vertical column (if the bottom-most level doesn't 'clog' with fines)
 
Do you know the water retention capacity (hydrostatically bound, both prior to and following repeated flooding)?
[vkn] I found the water holding capacity about 5-10% initially but reduced to 2-5% or it should be even less following repeated flooding.
 
'seems' reasonable - assuming percentage of the total pore volume only (not the entire bed volume)
 
Do you know the initial hydraulic conductivity (HC)?
[vkn]  The initial HC was about 1.1 cm/s. 
 
Have you assessed how much HC will reduce with (after) settling (following repeated F&D cycles)?
[vkn] After settling the HC was static at 0.69 cm/s.
 
That's a significant reduction in a brief amount of time.  I do hope that this rate of reduction slows substantially and/or halts.
 

Attachment: Sand data from the mining factory.

 

That's a mighty vague assessment on the 'fine' end of the scale.  Never heard of air washing before.  Do you know why they don't wash with water?  Is washing an option in future?

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We got some more sand to play with.  Here is an educational aquaponics system that we have been perfecting on.  Footprint per system: one square meter.  We intended to use sand media in three such systems for now.

 

Sand media added to the grow beds, furrows and crests made, plumbing and timer tested - found all okay today.  We would change water from the fish culture tank a few more times and will add fish by tomorrow afternoon.  

 

Hi vkn, I'm following your progress with interest, thanks for your reports!

 

I'm curious about the tanks you used for the educational systems - did they come as multi-level units or was that a modifcation you made? If so, would you mind telling me what you're using to support the top, which I'd imagine is relatively heavy.

 

I'm guessing that "fiber-reinforced plastic" might be what we in the US call fiberglass? They're certainly attractive with their bright colors. 

 

Thanks for providing an example of a small scale system - I was trying, based on the diagrams at the iAVs site, to visualize what such a system would look like - and the picture you provided really helped me a lot!

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Excellent tips.. we were discussing on those the whole day.  All points are noted and we would be implementing most of them here.  I really appreciate your words of wisdom, Dr. McMurtry.

 

We have a bacteria inoculation product with one of the Turquoise owner/operators.  I will share what we have when I see them tomorrow.  Also, there is a very mature compost bed at one of the  operators.  I asked to get this as well to see the moisture content and 'live'-liness.  I shall post the pictures should you be interested to watch what we have.  We would need to decide on one of these by tomorrow evening. 

 

On other questions,

 

Those data were from the sand test results.. initially done on buckets but later had to change to 2-L pet bottle testing.

 

What do you base your silt fraction estimate?

 

[vkn] I don't have a good answer to this question.  That is what the sand mining factory manager told to us.

 

Do you know why they don't wash with water?  

 

[vkn] The sand factory do not have a process of washing their sand with water in place.  These are builders sand meant for concrete and not for plastering.  They say none of their clients asked for it before.  We requested washing for an additional price but it did not work.

 

Is washing an option in future?

 

[vkn] I do not know.

 

Kind regards, vkn

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Hi Neighbor, my responses side by side.. please scroll down.

 

 

 

Hi vkn, I'm following your progress with interest, thanks for your reports!  

You are welcome!

 

I'm curious about the tanks you used for the educational systems - did they come as multi-level units or was that a modifcation you made?

Those educational systems were designed and manufactured by us at NARDC..  We are on the product development and improvement mode right now. The bigger challenge we took was to keep everything under one square meter footprint.  So, the grow bed is on top of the fish culture tank.  There are options to add more grow beds horizontally for people with more space (above ground).  One can have an iAVs SMC sand media culture, a DWC deep water culture, and a GMC gravel media culture system for comparison utilizing one fish tank.

 

If so, would you mind telling me what you're using to support the top, which I'd imagine is relatively heavy.

They are galvanized iron pipes, fitted perfectly into the grooves made within the FRP fish tanks and the grow bed above.  We made several strength and performance testing before finalizing. Those are the first 3 prototype systems operational now. 

 

I'm guessing that "fiber-reinforced plastic" might be what we in the US call fiberglass? They're certainly attractive with their bright colors. 

There are three colors we chose that suit our NARDC logo - green, blue, and orange.

 

Thanks for providing an example of a small scale system - I was trying, based on the diagrams at the iAVs site, to visualize what such a system would look like - and the picture you provided really helped me a lot!

I do not think this system is a replica of what is portrayed at iAVS.info site.  Please read more about the below-ground, on ground, above ground system designs provided at the iAVs site.

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oops, I worded that poorly - I recognize your design is not standard iAVs - but I like how compact it is and how it maximizes production space, something I was hoping to see in a small system. This design seems appropriate for urban applications or where a) one doesn't have large tanks or b) the ability/desire to dig large holes.

 

As you continue along the "product development and improvement mode"  I'll be following your progress.

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May 2016 bring you and family happiness, peace and prosperity.

 

Also to all Aquaponics enthusiasts New Year Wishes for Health and Aquaponics farming!

 

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As I write this on the first day of 2016, it is the time to reflect on the year and consider what strategic Aquaponics issues on which NARDC would like to concentrate in 2016.

 

Here are NARDC's THREE WISHES for Aquaponics in India in 2016!

 

1. Bringing Aquaponics to the masses! One issue continually raised to put people off Aquaponics is the cost of contruction and the maintenance of it. How to make small-holder farmers to gain access to these innovative Aquaponics techniques to produce a vital supply of nutritious food and to raise the standard of living? We would like to focus on this issue in 2016. Now that NARDC has been working on iAVs sand beds for the last 6 months, I wish some of these issues would most likely be taken care of in our new installations - reduced energy costs, reduced construction and operating costs, etc.. and so many other things.

 

2. Bringing consistent, positive message to go to the grassroot farmers in India who would like to adopt Aquaponics would to another NARDCs wish and focus in 2016. Lots of things to do via our Facebook Aquaponics Futurist page and through the social media groups and forums and to work with government organizations that we are associated with. We will also have our Easy info web page for Educational Aquaponics systems (Easy) operational in a few weeks from now.

 

3. Increase consistent quality Aquaponics Education workshops, design and technology knowledge transfers, seminars, talks to women self-help groups, etc. about the unique and special benefits of Aquaponics way of food production. Hopefully NABARD and Agricultural Development Banks in India would begin to help domestic and/or village-size Aquaponics farming in 2016. In particular we are looking at a "180 days project" for Kudumbasree kind of small units with less than one cent (40 square meter) land area. I will explain more on this later.

 

None of these wishes are too outlandish to us – all of them would have enormous impacts on Aquaponics future in India. Let us see how we at NARDC go in 2016. If we can get some traction on all of these wishes, we hope the Aquaponics industry in India will move forward in 2016 like you have never seen.

 

Your inputs are welcome!

 

HAPPY NEW YEAR!

 

Vijayakumar Narayanan

For NARDC

Nanniode Aquaponics Research and Development Centre

We focus on Aquaponics in India!

Edited by vkn (see edit history)
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Testing, testing..


 


Combination timers are being tested at Turquoise Aquaponics farm to shut off the various pumps used for iAVs sand beds at appropriate intervals.


 


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A special mention and a big thanks to Saju Thomas of Turquoise team for his meticulous care and efforts in understanding the whole operation quickly and setting up the timer unit all by himself. It works like a charm!


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Hi VKN,

 

Congratulations on this most recent milestone.  How many pumps does that timer set up control?

 

Gary

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Hi VKN,

 

Congratulations on this most recent milestone.  How many pumps does that timer set up control?

 

Gary

Happy new year, Gary!

Thank you.. This combination timer has an option to control 8 pumps but we are testing with 6 for now.

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From Turquoise Aquaponics farm, Bengaluru, Karnataka
Tuesday 7:21 AM

There was fog everywhere. 
Outside temperature was at 15 degrees. This is one of the lowest temperature we experienced this season.  Inside the greenhouse, it showed 18 degrees but the Aquaponics water was at 22 degrees celcius.

 
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Turquoise Aquaponics farm is almost ready for commercial operations. We are adding fish tomorrow.  Wish us luck!  


 


Here are some pictures from the facility as of today.


 


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Hi VKN,

 

Great progress so far there mate. You and your team should be proud & excited.

 

Im sure many eyes are watching with great interest, I am.

 

खà¥à¤¶à¥€ और बहà¥à¤¤à¤¾à¤¯à¤¤ के मौसम आशीरà¥à¤µà¤¾à¤¦
नमसà¥à¤¤à¥‡

(Seasons Blessings of Happiness and Abundance
Namaste)

 

Cheers

Joe

Edited by Toga (see edit history)
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