Backyard Aquaponics
A place to discuss aquaponics

I would like to build my own tank. Anyone ever done that? Built a tank I mean and if so, what was your design? Materials and general design.

I would like to build it from lawn timbers, 2 by lumber, plywood and a liner. I have in mind, for my first attempt, a 2'x2'x8' tank.

Tony

Do a search of the forum Anthony.... quite a few have built wooden tanks and lined them... and a few have done ferro cement tanks as well ...

My largest is 4'x4'x19' with a 12"-deep gravel growbed covering 4x16'. Bottom is ply on gravel, sides are 2x4 16" on centers, bottom of growbed is 1.125" ply with no mid supports. Liner is food-grade ldpe.

Next time I would use tie rods to prevent the sides spreading and a separate growbed rather than an integrated one. To check the fish I sometimes need to don wetsuit, snorkel, and mask and bring a flashlight. *grin*

I've seen pics on this forum of a circle made of fencing and lined with liner. A similar method would be to look for old above-ground pools (the ones with metal edges) and line that. Big, decay-proof, and cheap.

I thought this one was very interesting- a home made circular aquaculture tank in a size that is practical.
http://nsgd.gso.uri.edu/hawau/hawauh89001.pdf
This link is actually for backyard aquaculture in Hawaii but in Chapter 6- Basic Building Design, there is an above-ground tank heading, with a 12' diameter circular design. Lots of other good information in this manual too.

Above-Ground Tanks
A backyard tank can be constructed from
five sheets of 1/4-inch plywood, joined with
bolts and formed into a cylinder. Such a cylinder
(12 feet in diameter) can be built in small
backyard areas, and carried by three people to
its final site. The cylinder is lined with a
commercially-available swimming pool liner.
The 4- x 8-foot plywood sheets may be used at
their full size, or cut to 3 feet or other heights
before the cylinder is joined.

Other good sources for square tanks have been DIY aquarium tanks.

This is a Materials List for the above circular tanks- notice the supports are stainless shipping bands- I thought that was genius!!!

Materials and Approximate Costs for Construction of an Above-Ground Tank of 12 ft. (3.66 m)
Diameter
I. Plywood, exterior grade A/C, 8’x4’x1/4”,
5 sheets @ $13.00/sheet $65
II. Sealers
A. Water-seal wash, 1 gal 12
B. Asphalt emulsion, 1 gal 9
III. Fasteners, Banding
A. Stainless carriage bolts, 3/8” x 1 1/4”,
w. flat washers, lock washers, hex nuts, .50 ea 12
B. Stainless shipping band, 1/2”,
approx. 120’ @ $0.50/ft 60
IV. Liner, 16 mil, 12’x4’ 80
V. PVC, Schedule 40
A. 3” pipe, 16 ft @ $3.00/ft 48
B. 3” el-90, 2 ea @ $15 30
C. 3” union, thr male, slipe female 15
D. 3/4” pipe, (est) 40’ @ $0.50/ft 20
E. 3/4” ball valves, 2 ea 20
F. 3/4” unions & elbows, misc. 10
VI. Footing Pad
A. bricks, 24 ea @ $1.50 36
B. pea gravel, 60 cu ft 50
C. sand, 30 cu ft 25
Estimated Total $__________________

Here's my take on building tanks





There is 3 more of these under way

My main tank is a hole with some wood framing around the top to keep the top of the tank above ground level so that stuff doesn't get washed into the tank during storms. I think pond liner is pretty great. I use the thick EPDM rubber liners that are fish safe.

The biggest thing to keep in mind when doing above ground lined tanks is that fluids always try to spread and they will attempt to make anything flat bulge or spread. You need far sturdier bracing when making rectangular tanks than you do when making a round tank. (Curves and circles tending to be stronger naturally.)

I have tried a number of configurations and finally settled in on the heaviest timbers I can get, and heavy duty pond liners,

I have done large vats for coral growout with these of 18-24" deep, 8-12' long.

I find every 3-4' you need a center top piece to keep sides from bowing, the larger the timbers used the less bowing.

the welded framing shown is sure nice.

I am considering constructing one from 3mm Marine Grade Alloy, as i am a sheety and can Form and weld the tank up for minimal cost. (have made the odd 1000l tank or 2) is there any research of alloy tanks and weather fish like alloy or would i have to line it still?? also wouldnt mind making my grow beds from alloy... may have to do some research into fish, plants and alloy....

m3tal,

Welcome to the forum!

Yes, there are a number of metals and alloys that are VERY toxic to fish. Copper and galvanized coatings are chief, but I seem to recall aluminum is a bad thing, too! I would recommend a frame or steel box that is lined to be sure nothing toxic is introduced... Lining ain't cheap, but it is good insurance against trace toxicity..

CB

Cheers Mate glad to be here and a part of Aquaponics

Have come to the conclusion that i will definitely line some kind of frame or tank, it would be very disheartening to cycle my system and have it running nicely to find the addition of fish ends up in dead fish. then there is also the fact that aluminum transfers temperatures far too efficiently so if it was in the sun in summer i could see a huge spike in temp and vice-versa on a frosty night in winter.

have been toying with the idea of bales of straw to insulate it etc so i am back to the drawing board. i did see one of those big white tanks in a metal frame which is probably what i will go for and i will probably still line that as you dont know whats been in them although with this i am still worried about the heat/cold maybe still toy with straw bales to insulate.

would the possibility of a Long Narrow tank work very well say in the lines of 2400l x 700w x 700d (d being ground to sky) this would fit into my tight space very well, i am worried about fish not growing as much as they may feel there in a smaller tank.
i could build it from Gal sheet in a metal frame and line it. this would be 1176l with i reckon 1000 usable if it was filled 100mm from the top, this would also allow for easy insulation with straw bales which i think are the best organic insulation.

sorry for the long winded reply hahah

Cheers jamo!

I have had trout grow to 28cm in an aquarium that only measured 30cm X 120cm X 50cm (12"x48"x20"), so I would not be too worried about the width. I have found that sediment can build up in a long tank since it is hard to get the swirling motion to collect it in the middle. Perhaps a sloped bottom? Perhaps some bottom feeders like carp or cats that will move sediment around and prevent it building up.

My current big fish tank is two fencing panels (cattle panels) strapped together in a 6 foot dia circle and lined with pond liner. You can actually get tank liners the appropriate shape that would be even easier than trying to fold a flat piece of liner into a round tank. I did use some insulation and a tarp around the tank inside the fence panels but outside the liner. Been running this tank for about 11 months now I think.

I am no longer a supporter of wood and liner used together. I've had too many termite issues, they don't realize they have chewed past the wood till it is too late!

i went and looked at the big white tanks i seen today they have been filled with Truck wash and still have an amount of it in the bottom (prob 10lt) has turned me off them as i will still have to line them, i can get 3 sheets of gal for that and build myself a large steel tank then line that. i was thinking about putting a full line of 25mm PVC through the bottom of the tank with 8mm holes in it and run a small amount of flow through it to keep the sediment flowing around the tank. sloping bottom wouldnt be too hard either.

thanks for the input guys!!! im sure i'll be around a fair bit over the next few years looking forward to getting to know you guys and share success stories

Those tanks if they are under $100 grab them truck wash is easy to clean [pressure washer ]