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ated19

Some iAVS concepts and ideas

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One not-insignificant drawback of the sand bed design is that large quantities of appropriately sized sand can be quite expensive. A recent build I completed (two beds: 3ft x 12ft, 4ft x 12ft) required 2 cu yds of 'playground' sand at $150 / cu yd! In the big picture $300 isn't the end of the world, but that particular sand was the most expensive aggregate sold at my local rock yard, 5-10 times more than gravel or lava.

 

The price is not a deal breaker per se, but for those looking to DIY something as cheap as possible, it is a factor.

 

Anyways, this has got me thinking.....

 

Sand is a great fine particle filter. I've been experimenting with a single 5 gal bucket full of sand to filter/digest the solids caught in the Radial Flow filter attached to my 500 gal koi pond. It was doing great while the temps were cool, but with the last couple warm months this little filter can't keep up with waste production. Appropriately sized though it would work just fine.

 

My thought is to use the iAVS sand bed concept as a fine filter and mineralization stage, but modularize it, separate from the growing area just like we've done with dedicated solids and bio filters in other systems. Perhaps an ibc or two of sand would be enough. Obviously it's more about surface area than depth but I'd need to find a compromise using conveniently available materials and techniques. Finding the minimum sand bed area needed for a given tank size and stocking density would allow me to use a cheaper medium like 1/4" cinder for the grow beds, or DWC or NFT.

 

This would give me many more growing options and setups, especially if I simply added the sand bed filter to the drain of the solids filter. My fish pump could keep going 24/7 keeping them happy and healthy.

 

Of course I'm aware I'm just reinventing the wheel here...implementing a slow sand filter and disassembling the iAVS concept to use only the features I need.

 

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Dont know what size range "playground sand" is.  I used 5/20 sandblasting sand to fill my sandbeds for much less.  Been working fine going on 3 years now. 

If your plan is to filter your pond AND grow vegs, then consider the beds an investment.  Should give you good service for years with much less maintenance efforts than many other kinds of filters, and the plants' taking up the decayed/mineralized nutrients will help keep the water ph stabalized.  

I would expect you to be quite pleased with the pond/sandponics marriage once the system is stabalized.  Load the beds with plants and see what the system will support.

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On 10/17/2019 at 3:54 PM, ated19 said:

One not-insignificant drawback of the sand bed design is that large quantities of appropriately sized sand can be quite expensive. A recent build I completed (two beds: 3ft x 12ft, 4ft x 12ft) required 2 cu yds of 'playground' sand at $150 / cu yd! In the big picture $300 isn't the end of the world, but that particular sand was the most expensive aggregate sold at my local rock yard, 5-10 times more than gravel or lava.

The price is not a deal breaker per se, but for those looking to DIY something as cheap as possible, it is a factor.

 

The price of iAVs-suitable sand ranges from nothing to whatever washed and graded filter sand cost in your area.  How much you pay for sand ultimately comes down to what sort of effort you are prepared to put into finding it.  If you live in parts of Africa, for example, you will find it...in huge quantities...on the lee-side of sand dunes...for nothing more than the effort of moving it.

Sand is like any other substance in a market...the more value that it added to it, the more it costs.  Clean, sand - of the correct particle size range is valuable for what it has been demonstrated it can do when used in an iAVsf context.  It has to be measured fairly against the alternatives...but that's a problem because when it comes to solid media there's nothing that can come close to doing what sand can do.   When it comes to measuring it against DWC or NFT, you have to take account of the cost of the added infrastructure required by those methods...and you still haven't drawn level with iAVs in terms of productivity, resilience and sustainability.

Edited by GaryD (see edit history)

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I guess what I'm saying is that, given what sand cand do, we need to get a different perspective on it.  It should be more expensive that gravel, lava rock and clay pebbles.  Sand can do many things that they can't...so I'd argue that comparing them is futile.

Quote

 

Sand is a great fine particle filter. I've been experimenting with a single 5 gal bucket full of sand to filter/digest the solids caught in the Radial Flow filter attached to my 500 gal koi pond. It was doing great while the temps were cool, but with the last couple warm months this little filter can't keep up with waste production. Appropriately sized though it would work just fine.

My thought is to use the iAVS sand bed concept as a fine filter and mineralization stage, but modularize it, separate from the growing area just like we've done with dedicated solids and bio filters in other systems. Perhaps an ibc or two of sand would be enough. Obviously it's more about surface area than depth but I'd need to find a compromise using conveniently available materials and techniques. Finding the minimum sand bed area needed for a given tank size and stocking density would allow me to use a cheaper medium like 1/4" cinder for the grow beds, or DWC or NFT.

This would give me many more growing options and setups, especially if I simply added the sand bed filter to the drain of the solids filter. My fish pump could keep going 24/7 keeping them happy and healthy.

 

I respectfully suggest that your plan ignores how plants grow in soil.  There is no question that you could filter the water for a recirculating aquacualture system using sand filters...some of the biggest and most valuable fish collections in the world are protected by sand filters...eg the EPCOT centre...but iAVs is not just about filtering the water....but rather the creation of a mycorrizhae that interacts with the plants to produce the results of which iAVs is capable.

There really is only one way to know if your plan is successful.  You build a stock standard iAVs...and then you build your planned deviation....and then you measure the performance of both units.

Quote

Of course I'm aware I'm just reinventing the wheel here...implementing a slow sand filter and disassembling the iAVS concept to use only the features I need.

Your "need" is predicated on a false perception of the value of sand.   If you take a more informed view of sand, that "need" may change.

Edited by GaryD (see edit history)

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