Backyard Aquaponics
A place to discuss aquaponics

I definitely think you will want to set up a big system for CHIFT. The large block raceways that morning star uses have the bonus of being easy to partition off for grading and separating. If they are tall enough it would be pretty easy to have them over flow into on the ground grow beds that could be very large and then pumping up to any NFT or other planting methods.

I'm really not liking the solids having to go through the pump before getting to the grow beds.

TCL that's exactly what I'm thinking. Two large and deep tanks with a raised walkway for access.

What do you think of as large and deep?

So what type of fish are you looking at getting? Have you thought about getting some of those breeding colonies that produce only the male offspring of a particular color?

If you're going into it with the intent to produce that much fish... skip the headache of breeding/grading...... just get all male fingerlings... they'll grow faster.... proven...

Here's a harvest of a high density Tilapia tank....



And I guess there's a couple of ways of acheiving the water volume you're thinking of...

Inground.... large concrete tanks ... simulated ponds



Or above ground... smaller tanks in a controlled environment...

sorry to have to correct you again, Rupert, but fish density should be expressed in kg/m³/hr, not in kg/m³
as it is the amount of fresh filtered and aerated water that determines the density limits, much less than the tank size.
a small calculation will make you understand:
80 kg/m³ in a 1000 l tank with one recirculation per hour is 80 kg/m³/hr
80 kg/m³ in a 1000 l tank with two recirculations per hour is only 40 kg/m³/hr
80 kg/m³ in a 1000 l tank with four recirculations per hour is only 20 kg/m³/hr

this makes an enormous difference, not only on (natural !!!) DO supply, but also on solids removal which greatly influences DO demands
what is important is to adapt filtering capacity to daily feeding rates either by enough growbeds and plants or by settling and removing solids out of the system or by a combination of both.
density per volume has no influence on fish health by itself if you omit the recirculation factor.

greetings

Frank

Yep... you're right Frank...

Wasn't my intention to mislead Jazz.... or to try and explain the myriad of variables...

Just to give a "quick" example... to show the scale of things, particularly the minimum volume he was going to require....

Complete system plans are available.... at a large cost....

And I did allude to the necessity for sufficient filtration... be it growbeds or solids removal...

I still stand by my comment though... that above certain densities... you just can not infuse sufficient oxygen with normal air.... regardless of flow...

And yep, you can toss in variables like temperature, altitude.... etc...

It's up to Jazz to fully research the permutations, and gather the knowledge to undertake both the design and operation of a project this scale....

And he'd better do his business plan and cost analysis based on ALL the knowledge he can get.... this aint gunna be cheap....

And either needs to be done absolutely right at high stocking densities... or done over large areas at lower densities... whether that be pond or recirc.....

May well be that from both a cost and management perspective... that pond based aqua, or at least pond based aqua techniques in really large tanks... might be the way to go...

Good point frank

that is simply not true, Rupert
with flow, you can infuse all oxygen needed for whatever density
whether the fish will like excessive flow is another matter

frank

That would be a lot of flow

I daresay there must be a crossover point between the cost of moving a lot of water for aeration, and the cost of adding pure o2.

that is a problem for the accountant, not for the technician

frank

Thanks for the pics and info Rupe. TCL I'm looking at several options for tanks, but right now I'm leaning towards either twin 7 X 30' concrete tanks in my metal building or inground tanks of some sort in a large greenhouse or perhaps some combination. I'm going to Eustis Monday to look at some frames that are a little over 4000 sq ft. The decision to go in the greenhouse or metal building will partly depend on the outcome of my solar water to air heater that I'm building for this winter. If it does what I think it will, I'll be putting all the fish in the metal building enclosed by their own large insulated room. It's a lot easier to heat air than water.

As for fish, I won't be doing any breeding except a few pets for the wife. I'm buying all male hybrids probably from Aquasafra.

This project is in the very early planning stages.I started this thread only to find out what experiences other AP'ers have had. I've got journals of theoretical information, reports, studies, etc.....

But with said, thanks to all for your ideas and thoughts. I'll be asking for a lot more before this project is over.

Jazz

Try SRAC publication No 282.

So you can see the impractibility of attempting to oxygenate recirc tanks at high densities Frank..... the flow rates required for both water and air are enormous.... the water would be boiling like the discharge from the Hoover dam.....

Consider further.... air is 21% oxygen... and 79% nitrogen (mostly)....

It's not just the limitation of infusing sufficient available oxygen from natural air....

It's, perhaps more so, the fact that you're adding huge amounts of nitrogen to your system....

Loading a highly stocked recirc tank with excessive amounts of additonal nitrogen....

Just isn't a great idea Frank ......

Yep... you could probably scale up your nitrification bio-filtration etc etc.... but you just end up chasing your tail.....

And having the bank manager knocking on your door foreclosing on your loan....

you (and many aquaculturists) seem to make a habit of omitting a major factor every now and then, Rupert:
in this case tank volume and density which are not mentioned in the document


I like this comparison: surely you agree that the discharge of a dam gives huge aeration possibilities
much more so if this discharge would be spread over a series of cascades

I have taken the only available data (0.47-kilowatt) to calculate what kind of flow a reasonably efficient pump (57%) would produce @ 1 m head: not less than 1600 liters per minute or 96 m³/hr.
That is an enormous volume
I suggest that such a flow would be much much more than needed for DO demands
which again proves that aeration with air stones is not efficient

I suggest that the flow and drain in a growbed is much more efficient as it exposes huge surfaces of thin layers of water to equal surfaces of air. Growbeds are in fact huge trickling filters.
With the added advantage that the oxygen needed for nitrification is only partially consumed from the water, mostly directly from the air

as for the comfort of the fish: numbers can be very misleading
fish live in huge densities in schools in ponds and in the sea.
these schools move around at slow swimming speed to find the oxygen needed
though the above flow of 96 m³/hr seems huge, it is no threat to the comfort of the fish at all:
Spread over a cross section of 1 m², this means a water speed of 96 m per hour, only 1.6 m per minute, only 27 mm per second.
To compare: when strolling you easily walk at 3 km/hour, 30 times faster.

this again proves that density should be expressed in kg/m³/hr.

frank

470W pump that flows 1600LPM at 1m? can you point me to one, i want to buy 10!

have done a quick search and the ones i found that pump 1600LPM are 5.5kw