bigdaddy

iAVs Questions

53 posts in this topic

Hi folks,

 

I'm interested in the basic design of an iVAs.

 

I understand you have a planter box and a fish tank, preferably the planter box should be higher than the fish tank so the water from the planter box can run back to the fish tank. The drainage of the planter box to the fish tank is what I'm particularly interested in.

 

Does the water drain through a stand pipe?

Does it drain the same way we understand through the aquaponic systems we have been building? 

Is the drainage constant flow, timed or some other way of drainage?

 

Cheers.

Edited by bigdaddy (see edit history)
vkn and GaryD like this

Share this post


Link to post
Share on other sites

Good to see these basic questions and happy to answer these as I understood it from the master.

Sand beds do not need a bell siphon, stand pipe, etc. Have a one inch slit at the bottom near to the fish tank. I use a tank nipple/connector and seal it. Use a bucketful of gravel and/or a hardware cloth to cover drainage hole before adding sand to the filter.

Allow for ample slope toward the drainage end. Flood (saturate) beds, timer shuts off pump (at appropriate level), gravity does the rest.

Cycle-on duration using a timer will depend entirely on the exact hydraulic conductivity of the sand you use. On an average of my systems, it is 25 minutes flooding and 1-1l2 hours of drainage interval.

Hope it helps.

Edited by vkn (see edit history)
bigdaddy likes this

Share this post


Link to post
Share on other sites

Good to see these basic questions and happy to answer these as I understood it from the master.

Sand beds do not need a bell siphon, stand pipe, etc. Have a one inch slit at the bottom near to the fish tank. I use a tank nipple/connector and seal it. Use a bucketful of gravel and/or a hardware cloth to cover drainage hole before adding sand to the filter.

Allow for ample slope toward the drainage end. Flood (saturate) beds, timer shuts off pump (at appropriate level), gravity does the rest.

Cycle-on duration using a timer will depend entirely on the exact hydraulic conductivity of the sand you use. On an average of my systems, it is 25 minutes flooding and 1-1l2 hours of drainage interval.

Hope it helps.

 

Thank you vkn,

 

That is exactly what I was after.

 

If others have basic questions about iVAs, feel free to post them here.

 

Cheers.

Share this post


Link to post
Share on other sites

I have been operating with an IBC tank and two 3' x 16' sand beds for about 9 months. The ONLY filtration is the sand, after just a few days the little bit of entrained dust in the sand had settled out and the fish tank has been clear enough to see the fish even in 36" of water. The fish are happy and healthy....now if I could just get the pH to cooperate......

But that is for a another thread.

Chose your sand wisely, all sand is not created equal.....and your everyday quarry is not really equipped to answer the detailed analysis....test-test-test again!

I am convinced that iAVs is simple to operate and very robust.......mh

Here's a quick photo, complete with reflection....but it is obvious that the sand does a great job of filtering!

post-1196-0-66584000-1463360585_thumb.jp

bigdaddy and vkn like this

Share this post


Link to post
Share on other sites

I am convinced that iAVs is simple to operate and very robust.......mh

Here's a quick photo, complete with reflection....but it is obvious that the sand does a great job of filtering!

attachicon.gifimage.jpg

 

Just what do you mean by "very robust"?

 

So being that sand is great at filtering, but you can't eat the sand. So what are you growing in your beds?

 

Do you keep track of how many plants of each variety, per so many sq/ft of sand?

 

Do you also track what is produced to eat from the above?

 

Share this post


Link to post
Share on other sites

Hi folks,

 

Do I have this right so far?

 

The best type of sand to use is Quartz sand crystaline in shape 1mm-2mm in size and free of the impurities spoken about previously?

Take care in selection of the sand...Test test and test again to enesure the sand is correct?

No need for stand pipes, bell syphons and the like providing your bed has suitable slope on it and drain hole is at the bottom?

You can connect your drain via a nipple installed in the drain hole?

Cover the hole with pebbles suitable cloth or both to stop sand escaping?

 

Cheers.

Edited by bigdaddy (see edit history)

Share this post


Link to post
Share on other sites

Hi OP

Just what do you mean by "very robust"?

 

So being that sand is great at filtering, but you can't eat the sand. So what are you growing in your beds?

 

Do you keep track of how many plants of each variety, per so many sq/ft of sand?

 

Do you also track what is produced to eat from the above?
 

Read Mikes chronicles here http://aquaponicsnation.com/forums/topic/9675-iavs-in-oklahoma/ that should answer your Q's

 

cheers

Share this post


Link to post
Share on other sites

Good to see these basic questions and happy to answer these as I understood it from the master.

Sand beds do not need a bell siphon, stand pipe, etc. Have a one inch slit at the bottom near to the fish tank. I use a tank nipple/connector and seal it. Use a bucketful of gravel and/or a hardware cloth to cover drainage hole before adding sand to the filter.

Allow for ample slope toward the drainage end. Flood (saturate) beds, timer shuts off pump (at appropriate level), gravity does the rest.

Cycle-on duration using a timer will depend entirely on the exact hydraulic conductivity of the sand you use. On an average of my systems, it is 25 minutes flooding and 1-1l2 hours of drainage interval.

Hope it helps.

 

Hi VKN....I'm struggling with visualising the arrangement that you've described.  Do you have a photo of what you're talking about?

 

Mark used various methods but on his Ratio Trials, he created a 1/4" aperture at the end of the bed against which he placed pea gravel before filling the bed with sand.  When he was due to begin operating the system, he took a knife and ran it along the 1/4" aperture....slicing the liner the full width of the bed.....and that was it.

 

Hi folks,

 

Do I have this right so far?

 

The best type of sand to use is Quartz sand crystaline in shape 1mm-2mm in size and free of the impurities spoken about previously?

Take care in selection of the sand...Test test and test again to enesure the sand is correct?

No need for stand pipes, bell syphons and the like providing your bed has suitable slope on it and drain hole is at the bottom?

You can connect your drain via a nipple installed in the drain hole?

Cover the hole with pebbles suitable cloth or both to stop sand escaping?

 

Cheers.

 

The best sand is pure silicon dioxide derived of quartz rock (that is produces no chemical reaction in the presence of water)......in the size range 0.6mm - 1.2mm....with minimal material smaller than that.....free of silt and clay.  That's the ideal.  Variations on that are may work depending on the nature and scope of the deviation from the ideal.

 

Gary

Edited by Gary Donaldson (see edit history)
bigdaddy likes this

Share this post


Link to post
Share on other sites

I have to admit, I was skeptical of gravel keeping the sand in, but it worked pretty well.      A key factor  is the water is slow draining through the bed as compared to a gravel or other large media type bed.   I do rather like the drainage irrigation tubing with the screen shroud that Mike and others have utilized.

Edited by Ravnis (see edit history)

Share this post


Link to post
Share on other sites

Hi VKN....I'm struggling with visualising the arrangement that you've described. Do you have a photo of what you're talking about?

Mark used various methods but on his Ratio Trials, he created a 1/4" aperture at the end of the bed against which he placed pea gravel before filling the bed with sand. When he was due to begin operating the system, he took a knife and ran it along the 1/4" aperture....slicing the liner the full width of the bed.....and that was it.

Gary

The concept is more 'important' than any specific ways you achieve the desired outcome. I dont have a picture right now but I am building a new one soon. I shall try and remember to show you the arrangement I described. Edited by vkn (see edit history)

Share this post


Link to post
Share on other sites

The concept is more 'important' than any specific ways you achieve the desired outcome. I dont have a picture right now but I am building a new one soon. I shall try and remember to show you the arrangement I described.

I agree.  Mark used different methods on each of his trials.  My desire to see your arrangement is simply to see how different people use different strategies to achieve the same result.

 

Thank you.

Share this post


Link to post
Share on other sites

Hi,

 

I've tidied this thread up at the request of BD....removing all of the off-topic material and the very patient solicitations to the off-topic poster to desist.

 

Gary

Edited by Gary Donaldson (see edit history)
neighbor and bigdaddy like this

Share this post


Link to post
Share on other sites

Thanks Gary...

 

All righty

 

Is there any reason why the furrows are rectangular rather than round?

 

I'm think of say a half ball shape around each plant rather than joined together to make a long furrow.

 

Cheers.

Edited by bigdaddy (see edit history)

Share this post


Link to post
Share on other sites

Thanks Gary...

 

All righty

 

Is there any reason why the furrows are rectangular rather than round?

 

I'm think of say a half ball shape around each plant rather than joined together to make a long furrow.

 

Cheers.

 

 

So long as the plant crown is kept above water, I don't think it matters.  VKN has created four small mounds in his little Easy systems.  Of course, conventional furrows would be much easier to do if you were talking about large grow beds.

 

My advice is not to intellectualise iAVs.  Just get your head around it as to the basics....and do it.  There's always scope to innovate once you've got the fundamentals under your belt.

bigdaddy and neighbor like this

Share this post


Link to post
Share on other sites

Hi BD

Is there any reason why the furrows are rectangular rather than round?

 

I'm think of say a half ball shape around each plant rather than joined together to make a long furrow.

 

Cheers.

 

I don't think the shape matters much ? as long as they are present, and get to play their role.

I tried to demystify the building of iAVs earlyer here

 

Ande - nice find and thanks for trying.

 

 I'm compelled to point out that the inclusion of the furrow and ridge profile (surface structure)) - plus plants/roots -  in an iAVs filter-bed radically changes the infiltration boundary characteristic and extends/enhances performance - versus that of a flat/smooth flooded surface.  Don't believe that this is correct?  Fine, no one is forcing you to agree , modify your prejudice ... or to learn.  Then do your own experiment(s) and report both methodology and findings. 

 

I forgot to coment on the furrow and ridge profile at the time, because the thread went totaly offtopic/offensive and I got my handsfull moderating  :hot: 

but as BD raised the Q, here in this thread, I suddenly remembered  :) 

 

Anyhow the furrow/ridge profile is also a important feature when it comes to ice-breaking, if located in temperd/cold climate zone.

  Meaning it can/will still perform as a filter in a frost spel, and/or thru winter climate bellow freeze C/F.

 

cheers

bigdaddy likes this

Share this post


Link to post
Share on other sites

Hi folks,

 

I'm interested in the basic design of an iVAs.

 

I understand you have a planter box and a fish tank, preferably the planter box should be higher than the fish tank so the water from the planter box can run back to the fish tank. The drainage of the planter box to the fish tank is what I'm particularly interested in.

 

Does the water drain through a stand pipe?

Does it drain the same way we understand through the aquaponic systems we have been building? 

Is the drainage constant flow, timed or some other way of drainage?

 

Cheers.

 

HI BD......on reading your original post again, I realised that I had not answered your last question.

 

iAVs is designed for four irrigation events per day - at approximately two hour intervals.....during the daylight hours.  The details of this may vary based on things like climate, crop, daily temperature, etc.

 

You can see how iAVs works.....HERE

 

Gary

bigdaddy likes this

Share this post


Link to post
Share on other sites

HI BD......on reading your original post again, I realised that I had not answered your last question.

 

iAVs is designed for four irrigation events per day - at approximately two hour intervals.....during the daylight hours.  The details of this may vary based on things like climate, crop, daily temperature, etc.

 

You can see how iAVs works.....HERE

 

Gary

Perhaps that was a typo error and let me try to correct it.

They were each on for 15 min (this depends on other factors) in each cycle for 8 cycles each per day, in which case, the fish tank would be 'turned-over' (exchanged) twice each day.

bigdaddy likes this

Share this post


Link to post
Share on other sites

Hi VKN,

 

You're absolutely right.....on both counts,

 

It would only be four, if you're someplace like the Arctic where you're dealing with an eight hour day.  

 

The idea is that you start your first flood cycle at daybreak and the last one at the end of the day.  In the middle of Summer, that may mean up to eight cycles.....where in the middle of Winter (in most places) you may do it six times.

 

In general terms, you're looking to achieve at least two complete water changes in a 24 hour period.

 

It's also important not to feed your fish much later than 2:00pm.  That goes some of the way to ensuring that a complete water change happens after each feeding.

 

The broad goal is to feed the fish, have them eliminate waste and then remove that waste from the fish tank......so that the waste gets up onto the sand beds where it can do the most good and out of the fish tank where it will do the most harm - at least twice per day.  That leaves the remaining flood and drain cycles to deal largely with the dissolved wastes in the systems.

 

With iAVs, you can take a systems approach driven by guidelines (which is good for beginners or those who don't want to deal with the minutiae) or, as you're aware, you can take the time to learn and apply the underpinning principles.

 

As you've already suggested, you've tweaked this regime to take account of local circumstances.....and that's appropriate.

 

Thanks for pointing out my faux pas.

 

Gary

Edited by Gary Donaldson (see edit history)
neighbor and bigdaddy like this

Share this post


Link to post
Share on other sites

Gary said:

"It's also important not to feed your fish much later than 2:00pm."

Although I see the logic in this and agree in principal, my bluegills feed well before work but they are not much interested in food when my wife trys to feed them in the middle of the day. (No disparaging remarks about her cooking....). When I feed them about 6:30-7:00pm they eat like starving dogs. Without this evening meal I would miss out on much of the feed input to my system.

I don't recall seeing the feeding recommendation, was that on a document ...?

Edited by mhaigh (see edit history)
bigdaddy likes this

Share this post


Link to post
Share on other sites

Faux pas? No way. I thought you would correct your previous statement.

Tank exchange rates of at least 2 tank volumes/day is clearly not achievable by 4 irrigation cycles unless you plan to move 50% of the tank volume at each cycle. I found it difficult even with 6 cycles. These days I am trying to achieve 3 turnover per day with higher standing fish densities.

Edited by vkn (see edit history)

Share this post


Link to post
Share on other sites

VKN,

 

When I said "Thank you for pointing out my faux pas".....I was thanking you for drawing attention to my blunder or careless mistake.

 

I then acknowledged the truth of what you said by saying that the flood and drain cycle should operate every two hours (or so) during daylight hours.....hence my reference to six and eight times.

 

I hope this clarifies any misunderstanding on your part.

 

Gary

Share this post


Link to post
Share on other sites

Gary said:

"It's also important not to feed your fish much later than 2:00pm."

Although I see the logic in this and agree in principal, my bluegills feed well before work but they are not much interested in food when my wife trys to feed them in the middle of the day. (No disparaging remarks about her cooking....). When I feed them about 6:30-7:00pm they eat like starving dogs. Without this evening meal I would miss out on much of the feed input to my system.

I don't recall seeing the feeding recommendation, was that on a document ...?

mh, This is what Mark suggested on this subject.. Here you go.

 
I strongly suggest that you not feed at night.  In fact I recommend the last feed input of the day allow time for the feed to pass thru the fish and be pumped out/filtered by the sand before dark.  I generally allowed for a complete tank exchange (4 'cycles') between last feed and darkness.  I don't run any irrigation events at night.  In the tropics, perhaps you could schedule the last irrigation event for and hour or so after dark but after that wait until dawn.

 

I personally have no experience with your bluegill species and I believe someone else at APN has it.  I would suggest you to quit evening feeding once for all and try teaching your fish to accept the feed when you give it.  I think they all do.  You may want to apportion the daily quota of feed into two or three equal parts rather than feeding them to satiation at first feeding of the day.

mhaigh and neighbor like this

Share this post


Link to post
Share on other sites

mh, This is what Mark suggested on this subject.. Here you go.

 

I personally have no experience with your bluegill species and I believe someone else at APN has it.  I would suggest you to quit evening feeding once for all and try teaching your fish to accept the feed when you give it.  I think they all do.  You may want to apportion the daily quota of feed into two or three equal parts rather than feeding them to satiation at first feeding of the day.

VKN,

Thanks for the update.  I will try this over the weekend, since I can be around to handle all the feedings during the day.

 

I have been so focused on trying to maximize my feed input hoping that this would boost the nitrification, thus lower my high pH

 

Thanks.......mh

vkn likes this

Share this post


Link to post
Share on other sites

Hi,

 

A bit more information on the feeding regime associated with iAVs.....

 

Excerpt from JWAS article (et al),

 
“ … The fish were fed a diet of modified Purina Fish Chow 5140, with a minimum
analysis of 32% crude protein, 3.5% crude fat, and not more than 7.0% crude fiber. The
feed was not fortified with vitamins or trace elements (Table 2). The daily feed input rate
was based on a percentage of standing fish biomass as influenced by age and mean
individual weight (Pullen and Lowe~McConnell 1982). The daily ration was divided
equally into two feedings administered at 0800 and 1300 hours. The fish also grazed 
algae (Oscillatoria Vaucher spp., Cyanophyta and Ulothrix Kützing spp., Chlorophyta) 
which grew in the water and on the tank sides.
 
Fish food was analyzed using atomic absorption spectrophotometry for K, Ca, Mg,
Fe, Mn, Zn, and Cu, the vanadomolybdophosphoric yellow procedure (Jackson 1958) for
P, the Kjeldahl procedure (Black et al. 1965) using a salicylic acid modification for N, 
a curcumin method (Grinstead and Snider 1967) for B, and a turbidanetric procedure
(Hunter 1979) for S. Analyses are reported on a dry weight (DW) basis. " …

 

Share this post


Link to post
Share on other sites

Hi,

 

During this morning's chat with Mark, he reminded me that there is an organisation called the American Standard for Technical Materials (ASTM).  They have a standard - C33 - for construction sand.  That specification requires that construction sand will not contain calcium carbonate.

 

If a contractor builds a bridge or a hospital or anything else, he specifies this material....and that happens in Texas, Oklahoma or anywhere else.  The C33 standard is not only relevant to the US.....it will apply anywhere in the world that it is quoted.   Having said that, there are similar standards organisations in most countries.

 

Incidentally, that C33 standard is available for sale but you won't like the cost......but then you don't have to have the standard; you just have to know what it stipulates.

 

It follows, in my mind at least, that if you contact a sand vendor and ask (in writing) for sand which meets the C33 specification, and he supplies you with anything else, you have the grounds for a legal remedy.

 

By the way, Mark ordered “washed builders’ sand†(that's what it's called on the East Coast) for his projects.  He never quoted any other specification or anything......and he got the "correct" sand straight off the bat.

 

I suggest that anybody who is having difficulty with accessing sand of the correct type tries quoting this spec - and see how you get on.  Don't mention what you want it for.....just quote the C33 standard....and see what the vendor is able do about your request.

 

Gary

Edited by Gary Donaldson (see edit history)
Ravnis and neighbor like this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now