Backyard Aquaponics
A place to discuss aquaponics

This one is double layer of bricks with 4 in concrete in center 6 1/2 metre dia 2 to 3 metre deep

Concrete may be a good option but there are others depending on space, access and other site conditions.

There are a number of options including poly tanks on the market designed to be buried (I'm not sure what sizes) and any number of things that hold water, can be made to hold water or that may have a liner thrown inside them. The simplest option would simply be a hole in the ground with a liner. Often these are called pools but if you needed the m2 in garden area you could cover it with a deck or some other roof. THis is something you would have to do for almost any option since the large concrete tanks that have structural roofs are rather expensive. Money spent on beams and decking/roofing should be less than money spent on concrete.



If you where building an above ground tank that would be a consideration but since your talking about a below ground tank the problem is the soil pressure collapsing the tank rather than the water pressure causing the tank to leak. Besser bricks could be a great option to build what is essentially a retaining wall to hold back the surrounding ground.

Stuart

PS 20,000 liters isn't necessarily a lot of pressure. In fluids pressure is a function of depth. If the tank ends up being 2m x 10m x 1m deep thats not a lot of pressure at all but it is an excellent fish tank.

you found THAT at the tip too f n f??????????

I told everyone that he won the scrounging contest

Provided the proper reinforcing was used when building the besser block structure (which would probably include filling some if not all blocks with concrete) then there wouldn't be any issue with outward or inward pressure I wouldn't think. Would cost a fair bit though I suppose.

Over here a concrete 20000g (92000ltr) costs about $6000.
30000g (132000ltr) about ($9000) tin lid included.
bessa block Mmm don't do it, there are other ways...

Oh KP a good concrete tank will last 100 years+ and if it did form a crack then that can be repaired. Liners cost heaps... about $3000 for 20000g unless you have centre pillars to hold up the roof then you can add 50% for boots(feet).

Soil walls eventually cave in, they need to be shotcreted and that is way to rough for a liner.

spot on with the pressure, but a tank with those dimensions would suffer much more from evaporation in summer than one that was deeper with a smaller surface area.

The other thing I like is, dig a hole, drop the tank in and backfill it. Job done. Once that is done, I can set up the greenhouse(going over the tank) and set up the AP system. Then sit down and have a rum......or three.

somebody link to the thread with the tank set in crusher dust........which member was that?

Hey C1 you're the expert, but 100+ years is a lot more than I was aware of...
What exactly are 'boots'?
what about a plastic tank rather than a liner?

I have been told that you can't put normal plastic tanks in the ground. the movement can crack them and if they are empty and water gets in around them, they float and lift out of the ground.
There are specific underground plastic ones, but the price is extravagant.

boots for the 'legs' of the roof, some tanks have trusses others have less er engineering and need 'legs' to support the roof.
100 years is not very long, think of the structures (ie bridges) in your city made of concrete, they withstand much more extreme conditions than a lowly old tank.
The tanks made of concrete with todays techniques and contiuous pours will last shyte loads.

as I said : you are the expert. Perhaps my ideas are outdated, as the info has all come from preconceptions my old man has at the farm



do you mean the roof too?
If so, how do you get the mold out after? or is it left in permanently?
Is that odd coarse chipboard still used to support concrete roofs when poured?

mmm...don't mean to be synical but you prolly need to read your siggy
to get where I am coming from

my limited experince with concrete tanks on farms is that as long as its on a good base it will last donkeys years

if its just on a sand pad then it will errode ( or the stock will erode it for you ) the tank will move and then crack