I just searched on this forum for "iAVS" and found it was only mentioned by Gary Donaldson and another person once respectively. No one posted any pictures about it. I thought this permies group would be the best place to at least talk about and try it.
Anyway, I have done some home work and primary tests. But I am in the process of purchasing a home and planning to try it in the backyard, so I am switching to it but not in the full scale. So I do not have a lot of pictures to show it either. I just finished posting an article about it on my blog so I just post its link here, hoping to find someone who are interested in it as well.
Just to add one ore point... since I am going to place the whole iAVS setup in a greenhouse (with both solar thermal and geo thermal air to maintain the temperature), sand acts as a better thermal mass than expanded clay.
I have also been reading about it and hope to set up a system, but have not yet done so. I have read that the sand is supposed to be "inert" (won't react with vinegar), so my locally-produced sand probably won't work because I live in an area of pure limestone and they make sand by crushing rocks. I also read the sand was not supposed to be too fine--a mortar sand would be good. Lastly, I read that the top and the trenches should be level, but the bottom of the sand container should be sloped, so that water distributes evenly across the top, but still drains. For longer systems you should use perforated drain pipe to help flow. Typically the pump runs for 15 minutes every 2 hours to flood the sand, which not only waters and fertilizes the plants but aerates the water.
From what I have read this was the original design and is superior to aquaponics systems using clay balls or gravel. Supposedly someone took the design, commercialized it, but in the process used gravel because they did not have sand and did not think it mattered. Apparently it does matter, and sand is supposedly superior to other options (cheaper too). I recently joined a Facebook group for iAVs that Gary Donaldson manages: https://www.facebook.com/groups/1318946951452383/. Within the group you can access quite a few files from the left menu.
I too would love to hear of any experiences with these integrated AquaVegeculture systems (iAVs; also called sandponics).
Kevin, focus on the big picture. As long as the fish waste is not ended up at the bottom of the grow bed, you win.
As for the sand, I am testing the Play Sand I purchased from Rona (I live in Canada).
Yes, maybe this type of sand is too fine but I still have hydroton and simply place hydroton at the bottom and then add my sand. Just in the testing stage so that I do not need to follow every detail of iAVS, otherwise you will never be able to start.
BTW, I have not placed any fish yet so that I can add whatever I want to test. For example, I added a whole 4L milk bottle of fermented urine to the sand to see how clear the water be coming out of the grow bed. Well, the result? Clear water.
When I started my aquaponics, (with sand) I hadn't heard of iAVS. I was just trying to prove to myself that the concept would work for me without spending much money. I had leftover sand from a project, so I tried it. It was a slow start, but it works. It improves each year, presumably because organic matter acumulates. Or because the bacteria (and fungus?) population increases and becomes more balanced? My setup differs from proper iAVS mostly because I don't have the trenches and ridges. I basically dug one trench around the outside, once I realized the water wouldn't go through the sand as fast as it pumped. I had to redirect it or it would submerge everything. Here's an out of date picture:
I've not posted much about it here, because I didn't know if there was much interest, nor whether I had anything to contribute. I will post here in the future, now that I know. Here's a link to where I did post about it for a while. By the way, the linked thread mentions the use of fertilizer. I only did that during that summer. The next summer, I tried not using it, and things kept improving anyway.
T Melville, your link led me to join yet another gardening forum!
So far, it seems like you have to build up the soil, as if it were, well sandy well drained soil that had a hard time holding onto nutrients.
You even mention adding sticks, etc to your grow bed.
I'm assuming you don't use a bed of woodchip because it wouldn't filter the water, but actually pollute it?
Sandponics seems like growing in a sand filter, where the the growing gets good once the filter gets dirty.
I would be tempted to use a woodchip filled prefilter in line with the sandbed, to speed up the process of "dirtying" the sand.
I suspect I am missing something about the sandponics concept, because I don't see as more than a planted sand filter.
I used sand because everyone seems to use inert, (initially) sterile, extremely well drained media. I've seen youtubers remove roots and dead material and keep organic matter down. I never got it. Seems to me organic matter is great, provided drainage remains very good. The draining of the water, and replacement with air (Without allowing media to become dry.) makes my sand into a biological filter. It harbors a lot of the bacteria that converts fish waste into nitrogen. (The nitrogen cycle.) It may be that the plants also like the constant moisture with incorporated air, I really don't know.
I would really like to grow/rear fish. Unfortunately it will most likely be in IBC 300gallon containers.
I know that for others installing a half acrepond is an easy mater and its a much more natural system, sadly I am not able to do that.
Could I use the fish tank as a compost tea brewer? A bag with worm compost + a dash of seasalt/sea90 + EM + fish food + airstone.
Could I do a foliar spray with this weird fish tank compost tea?
Could I do dripline fertigation with this?
Buying fish food is similar to buying chickenfeed, so it doesn't bug me too much. And I am sure I could grow some feed onsite like worms, duckweed, etc.
After the initial fill they dont use that much more water than, chicken either.
Between the airstone and sump pump. I wonder how much electricity is being used.
With iAV, the pump is on for 20min and then off for about 100min. So 1/6th of the time.
Do I need to do a full 300gallon turnover in that 20minutes. aka a pump rated for 900gallon an hour @ 73W/hr or 146W/day with 1ft head.
I would need a 1CFM at 1.5PSI air pump using 25W/hr or 600W/day. For a total of 746W/day.
Would you all use different air pump or water pumps? How does my numbers compare to whats out there, hopefully mines are too high?
In my test system, I happen to have a spare pump there and it is really powerful, I can only run the pump for 1 minute to fill to the upper water level in a barrel (supposed to be fish tank but no fish in it while I am doing the testing). I use an airlift pump running all the time to pump water slowly from there to the grow bed and also to aerate the water. And I use a siphon and an H-shaped device made based on the following video so that the fish tank water level will not go below a certain limit:
iAVS was well tested and researched by the original inventor Mark McMurtry. I will follow his advice properly once I get our property (my wife and I have made the offer and got the mortgage approved). I will do it even before I build the greenhouse to cover it - the spring is coming :-)
Location: Massachusetts, Zone:6/7, AHS:4, Rainfall:48in even Soil:SandyLoam pH6 Flat
I really love this H-shape siphon device, that has the safety feature of not allowing the tank to ever get empty by accident.
I have a few questions.
Most iAVS systems seems to ask for a 15min to 20minutes runtime for the pump, with your system configure for only 1minutes, how does this changes things?
Whats the stats on your powerful test pump, "mine's" is 900gallon/hr at 73W/hr, with daily totals of 2hrs (6X20min) and 1800gal (6x300gal) and 146WHr (6x24.3WHr)
How many times per day are you running the pump? most iAVS system call for 8 times for 15mins or 6 times for 20minutes, a total of 2hrs in 12hrs and a 12hrs night rest.
Based on what I have seen, the 'air pump' oxygenated water is returned directly to the 'fish tank" for the fish, yours seem to be going to the growbed, what have you observed so far?
How much energy is your air pump using with the 24hrs runtime? For me it is 25W/hr or 600W/24Hrs. I am very concerned about total energy used per day.
Based on what I have read, the sand grow beds get a "no watering" night rest. You are slowly watering 24/7.
Did you read the same thing about no watering at night. I find that to be very shocking but it is suppose to work.
As for the 24/7 running air pump, its power is only 12W. With the h-siphon and H-flow thing, the water level remains constant even though the airlift pump can still pump some water out - it simply goes back to itself once the water level comes to the limit. That is why I say it simply as an aerator rather than an airlift pump after this, until the next cycle of water pumping by the water pump.
I just watched the video you linked. I suspect that guy has to clean his media more often than me, because he needs water to move through it more easily than I do. He uses a bell siphon, so I assume his pump runs all the time. To avoid anaerobic conditions, he needs almost all of the water to run horizontally to the siphon, then be lifted over the inner pipe that sets the maximum fill level, quickly and easily. If it develops enough flow resistance and allows air to be drawn from the surface MORE easily, his vacuum will break and leave a bunch of water behind in his sealed tub.
I don't have that problem, and won't until drainage becomes truly awful. The reason is less in the vein of the 6 "P"s, and more in the vein of "Always hire a lazy man to find the easiest way to do a job." (6 "P"s = Proper Prior Planning Prevents Poor Performance!) My grow bed is the top I cut off of the IBC tote. It has a large lid for filling, about 8" - 10" across, with a smaller plug threaded into the middle of it. The smaller plug leaks a little around the threads. Where I made the hole for drainage, there is also a slow leak. I couldn't be bothered to master the making of a bell siphon, so when I failed to make it work in an hour or so, I opted for constant flooding instead. Later, I followed some good advice and went flood and drain, but by putting my pump on a timer. Then I was unsatisfied with how quickly it would drain (through the leaks) so I pulled out the stand pipe that sets my maximum fill level, and drilled a hole just above where it joins the femail connector, then put it back. My pump still fills it faster than the leaks drain it, and the grow bed is directly above the fish tank, so I never fixed any leaks. So when my pump shuts off, my water continues to drain straight down for hours before it comes back on. It can move slowly if it wants to, but it never has to be lifted out. As the water drains, it's replaced by air, so it would take near total clogging to go anaerobic.
On the other hand, my system is still young, and still hasn't reached equalibrium. I won't clean it while it's still improving, but I never know when it might take a turn for the worse. Time will tell. I'm just observing as I go.