Backyard Aquaponics
A place to discuss aquaponics

That is of course if we consider F&D as the only way to go.
And if we only consider that we have to have 'conventional' grow beds.

Are you thinking about beds that drain straight back without a flood cycle? I thought the general consensus was that floods are needed for filtration.

The idea of a single (fish) tank, with the GBs draining striaght back appeals to me a lot. Very simple, the least amount of hardware and plumbing.

When I first joined I asked a daft question, re drip feed, this was because I had kept fish and done hydro but not combined.
If you only require the plants to mainly remove nutrients ie you run a seperate crap removing biological filter, the GB's can be differently designed. You will get told that problems will occur, if you run straight through, because the media is not wetted evenly etc etc etc. My current thinking is using plant pots in a trough (with a few more holes drilled in the pots), you dont drip feed but use a small header tank which F&D's. (loop,bell,flout or autoflush). Actually its a bit more complex than that, but dosn't have to be.
The hard bit is balancing the flush to the pots but black retic poly and fittings are as cheap as it gets.

So with that system there'd be no need for a large sump, just the header tanks.

I like the idea, pls be show to make a thread when you start building.

When you cant afford tanks you would just dig a pong and use "drillers" clay or a thin layer of cement and paint to coat the ground. Many times in countries where you can not afford to buy tanks you can get labor cheap, so seven if you refinish it every couple years it would be ok..

Unfortunately, I will be going with a sump, I like constant height in fishtank, pump in sump tank. And it gives me somewhere (between the two) to put in bio filter/cleaners.
No worries with the thread, will be slow though, don't pay for labour or equipment.

How exactly can circulating water provide enough oxygenation? Seems that there would be a need for at least one small pump to spray a few streams of water through the air into the race or, perhaps, the axial pump would need to lift the water enough to allow for a small waterfall. Either that or an air pump, which Im not fond of because all energy put into compression is lost as heat.

dan, at the pressure the air pumps run at what % is really going to be lost as heat?

I assume frank is thinking of surface agitation providing O2. This may not be enough having seen the monster 1300rpm paddle wheels used at the trout farms

My long answer before was meant to answer the question for a poster about could a bathtub serve as a header tank for a 24 hour period. I think part of the question included no electrical input and the water would be moved from sump to top tank once per day by human using bucket.

Such as system can provide aeration since the water lifted to the top tank would be trickling into the fish tank providing a small amount of aeration or better yet, a small grow bed that would flood and drain by auto siphon providing more air to the fish tank due to the extra splashing. Then the fish tank overflowing by SLO into another small grow bed which filters out more solids to keep the sump tank fairly clean and aerate the water going into the sump tank as well.

I'm not saying that the way I described is the best way, just a likely way to set up something that is only powered by a person with a bucket once per day and from there runs by gravity.

Needing big tanks is the huge drawback for such layouts.

Eek! 1300 rpm.. Or the pure o2 injection.. How can a farm make a profit if they have to inject oxygen all the time? Even an oxygen concentrator is quite expensive.

Has there been any work on oxygen levels vs agitation per square meter water service per fish?

sorry guys, but I am not going to repeat for the umptieth time all that I wrote
TMO the aeration effect of bubbles at the depths we use them is negligible
please do a search on diffusers or airstones to find out why I think so

Steve: for monster densities you need monster aeration
the trolling motor must at least bring lots of water to the surface, so must have an inclination

or it must be installed in a tube or in front of one so you can bring all or part of the water above tank level to a gutter, from which you can imply all methods of passive oxygenation you can think of.



frank

This is along the lines of what I'm thinking, we have cheap labor. However the concrete is a problem, if not done right it will crack. A better option is pond liner, we're in live (Thailand) produces quality pond liner, however it's all for export. Apparently you can but rolls with a min of 200m, although I'm having trouble finding a supplier.

If you were looking to water GBs only a couple of times a day, with no floods at night, NFTs with small pumps would seems the best way to get the needed aeration.

If i win the lottery i`m having one of these..overkill for a pond but ok for a small lake
http://www.oloid.ch/frame.php3?lang=en& ... oid_typ200
Not sure how you`d work out the efficiency figure though.

At what depths would bubbles not be negligible aeration Frank? Any?

I keep 50 larger fish happy in 55000ltrs with air stones. And I only had 800lts of gravel for a while and the water was not going through all of that. It is easier to just add the air to cover yourself. Even Frank has to run low densities because he relies on other methods of getting the o2 into the water. I'm sure he will get it running eventually but for the most of us it is a question of why bother. I like to run deep GB's so once I get enough of them online it would take care of most of the o2 problems but I would still leave the air stones going because I don't see the need for a balancing act where the flip side is stressed or dead fish. More air = happy fish.