Aluminum fish tank?

[Viktor Jarikov]

Does anybody know whether people use aluminum to build fish tanks? In the stainless steel fashion - 3 walls and bottom; and a glass/acrylic 4th wall or, rather, window.

Anybody sees pros and cons?

Google search is not very fruitfull. This is the most helpful info I found:
http://mfse.net/

Does not look like it is done much. If yes, I wonder what the reason is. Seems like a logical choice of a material, much cheaper than stainless steel and far, far easier and cheaper to weld. Sure, salt water corrodes aluminum but I am talking fresh water.

Is there an expert out there on stainless steel tanks know-hows, essentials, and pros/cons?

[Bas Pels]

I heard of someone, he sells motorbikes, and does a lot or repair himself, in the Netherlands who tired it.

The calculations resulted in 'too expensive as an alternative for glass or steel'

AOn a sidenote, aluminum reactin with oxygen produces a compound - aluminumoxide - which is dangerous for fishes. It does not dissolve rapidly, but in case of a pH above 8 or below 6 it will react to give toxic new compounds - Al(H2O)5(H3O)4+ or Al(H2O)5(OH)2+.

Therefore the aluminum will need to be coated - with a guarantee the coating will not scratch. I'm afraid not many suppliers will provide such a guarantee

[Suckermouth]

Is aluminum cheaper than wood? I know wood tank construction instructions have been on the internet for years.

[MatsP]

I would add that coating aluminium with any form of varnish/paint is quite difficult, because of the hard, smooth surface that the aluminium oxide forms. When they paint Land-Rover (offroad cars), they use an acid bath [phosphoric acid, I believe] immediately before the paint goes on, to etch the surface and make it more "grippy" to paint.

And no, aluminium isn't a cheap material - it's very good in some other ways, like it's low melting point and ability to withstand corrosion and low weight - it is relatively easy to shape into almost any shape. The drawback is that it isn't very strong, so although it's light, it requires more material to make it as strong as for example steel - it's still better, but it works best for things where high strength is not the key part.

Wood is a good suggestion... Easy to work with, and known to "work".

--
Mats

[Viktor Jarikov]

Thank you, friends.

The calculations resulted in 'too expensive as an alternative for glass or steel'

1. vs just steel - I'd agree. vs stainless steel, the info I was told by a local Naples metal fab co. disagrees - stainless steel welding process is extremely slow and tedious - aluminum is a breeze in comparison.
2. size surely matters in this discussion. sorry, forgot to mention: we are talking the smallest tank of 500 US gal, smth like 8'x4'x2.5' and the biggest 20,000 US gal, smth like 30'x15'x6'. Hence, forget about glass. I need above-ground pools/ponds with glass/acrylic window(s).

On a sidenote, aluminum reactin with oxygen produces a compound - aluminumoxide - which is dangerous for fishes. It does not dissolve rapidly, but in case of a pH above 8 or below 6 it will react to give toxic new compounds - Al(H2O)5(H3O)4+ or Al(H2O)5(OH)2+.

Therefore the aluminum will need to be coated - with a guarantee the coating will not scratch. I'm afraid not many suppliers will provide such a guarantee

Aluminum oxide, AlxOy-stochiometry varies, is, of course what makes Al inert to water and air. It's an excellent, hard, smooth, super-chemically-inert, super-hard, thick coating in and of itself, reminiscent of silicon oxide SixOy, which is sand/glass. Are you sure it is realistic that it can hurt the fishes
-- with pH within 6 to 8 and
-- in a flow-through system (I am not looking to recycle and biofilter the water - one inlet and one outlet; the flow would be such that 100% of water would be replaced in one week)?

Or is it just in theory? People use Al pots and pans for ages and scrape them mercilessly all the time and cook stuff in them that often has pH outside of 6-8. No one blew the whistle yet, afaik? Of course, fish are not people.

If it needs to be coated indeed, then it's a bummer but I will look into it. I'd coat it myself, perhaps with epoxy preceded by some etching agent - I am sure epoxy people will tell me or already have a solution to coating Al with epoxy.

Is aluminum cheaper than wood? I know wood tank construction instructions have been on the internet for years.

Sorry, again I was too curt. I'm shooting for "maintenance-free and infinite lifetime", so to speak, outdoor exhibits, while understanding these traits are not achievable but nevertheless, the closer I come to these, within my affordable budget, the better. Even pressure treated wood may not suffice. But, Milton and Mats, please elaborate. Sure, I've read plenty about plywood tanks - is that what you had in mind? I've considered things like wood+sealant and also things like liners and discarded these possibilities for now. Still, does not mean I am closed for discussion and learning - that'd be stupid and arrogant.

The drawback is that it isn't very strong, so although it's light, it requires more material to make it as strong as for example steel - it's still better, but it works best for things where high strength is not the key part.

Yes, it bends and bows. I hope it can be reinforced cheaply with ridges, angles, braces, etc. of Al or other material. I am not fixated on Al though yet. I am just mulling it over with your, guys, great help.

[Viktor Jarikov]

thought i'd cite a short exchange with Jonathan Strazinsky

VJ: .....i know you have a stainless steel tank; is it good? can you give me any tips, user know-how on it? i am pondering and collecting estimates for my exhibits made out of fiberglass, concrete, or stainless steel... do you know if people make freshwater tanks of aluminum?

JS: If it were me taking on this project I would consult the ppg aquarium, the atlanta aquarium and other large facilities to see what they did. I'd even arrainge for behind the scenes tours...

VJ: I did that and even behind the scenes tours to some extent at several public aquaria. The ones I saw all used poured concrete of tremendous thickness but they are usually far deeper, 10'-20', than anything I plan, 2'-6'. Also, they are all inside exhibits, built inside buildings, most likely along with the buildings, thus convenient and obvious choice of material. Mine will be outdoors, just under a roof or in a green-house-like setting.

The costs for fiberglass, concrete, steel, and aluminum are roughly (within a factor of 2) comparable but I'm still collecting more concrete (oops, meant as in precise ), easy-to-compare estimates, and trying to learn pros and cons of each of such tanks.

JS: I'd probably go with the concrete, it's tried and true... Some hatcheries down there use concrete coffin boxes....

[RickE]

How about something like this Viktor http://www.genemco.com/catalog/pdf/BBCF ... oktank.pdf. Pop a window in one side and you're done. Don't know what the costs are like though...

[Bas Pels]

@ costs, this is, obviously, dependent on the people you work with. The man I've heard about was in NL, talking about a 2000 l - 550 us gal tank

@ Toxicity of aluminium, I've heard in the south of the UK there are areas where the water supply for tapwater is made of aluminium piping. These areas also show a higher incidence of old age dementia. For me, that was reason enough never to cook in aluminium again.

However, we are talking about tanks. In a fish tank there are more chmicals around - ammonium nitrite, nitrate, and so on. Ammonium is able to attack aluminiumoxide and will dissolve the tank. This is no reason to fear leaking, but it will increase the amount of dissolved aluminium compounds

I've heard of people making hoods for their tank, using uncoated aluminium. This metal attracs condense, and the condense (very soft, saturated with CO2) will contain AL. Fish have died from this.

So therefore, regardless the costs (and I think these will be huge) I would advise against using AL for a tank

I studied chemistry, more precisely inorganic chemistry and to complete this I spend a year in ecotoxicology. I thnk i have both theoretical knowledge and a practical eye, having 30+ tanks.

[apistomaster]

Hi Viktor,
Have you heard of this company?
http://www.isshamaqua.com/construction/

Reinforced concrete may be the lowest cost form of construction for very large aquariums and perhaps the most well suited materials for outdoor exposures.

[Viktor Jarikov]

thanks everyone, again. Yeah, Bas, I am not too hot on Al either but just doing the due diligence, I guess. I think I caught some things on the web about Al tank covers. Gotta go back and read up more on that, at least. And yes, I remember the fellow chemists

Larry, what do you think of this? 22,000+ US gal for $14,000 (no windows) is not that bad and competitive in price with concrete. It's built for outdoors too. I am taking off in 15 min to visit the owner, Jack, in Homestead, FL.

http://www.aquaculturetanks.com/index.html

[apistomaster]

I hadn't considered fiberglass. It takes a leap of the imagination to think of having tanks as large as you have in mind but Dolphin definitely has some nice options.
I would miss not having a viewing window but the water clarity has to be perfect.
The other problem with a window is it should be viewed from a darker area than the tank is lit in order to see very far and minimize reflections.
I wonder how one would transport these large pools if they are of monolithic construction? I looked quickly at how they make the larger tanks in sections to facilitate transport. Clever.

[Viktor Jarikov]

no, Larry - the windows are a must. they can install windows in almost any of their tanks, even round ones (rounded windows would go into the round tanks, of course).

do you know if polycarbonate and lexan are inferior to acrylic in scratchability or any other trait? I've read on the web people write stay away fro polycarbonate and lexan because they scratch 10 times easier than acrylic (which already scratches easy).

yeah good point about lighting - I must think that through

yes, again, as you said, the tanks are sectioned; they are monolithic up to 8'6" in diameter (if round)

here is their competition in small tanks http://www.aquaticeco.com/subcategories ... ith-Window

$2000 for a 700 gal, 8'x4'x3', not bad at all.
Larry and All, do you know of any one who has first-hand experience with these tanks?

[apistomaster]

Viktor,
Google "scratch resistant transparent plastics"
You will find that the different material each have their pros and cons.
Lexan MR 10 is a plastic coated on both sides to improve the material's scratch resistance.
Polycarbonate is used for the canopy of the F-22 Raptor, the world's most advanced and most expensive fighter jet. Lockheed Martin must have had their reasons for choosing this material for the plane's canopy. Maybe it is the material used in airliner windows? I haven't delved deeply enough to know.
In general, the harder a material is the more brittle it becomes. This is a consideration for applications which are subject to higher stresses. This can be an important consideration for viewing panes depending on the choice of fastening and sealing. If you have to drill for bolts that is a source of potential cracking during drilling and/or the concentration of stresses at the bolts. Sealant compatibility would be another important consideration.
Most of the transparent plastics are available in coated, scratch resistant forms.
They each have varying degrees of resistance to UV radiation caused degradation.
I think I would find out which of the different window materials are favored by these tanks' builders. They should be able to provide good advice.

[Viktor Jarikov]

How about something like this Viktor http://www.genemco.com/catalog/pdf/BBCF ... oktank.pdf. Pop a window in one side and you're done. Don't know what the costs are like though...

Thanx, Rick. I am also looking into polyethylene tanks, such water storage tanks, that are abundant and can be found for $500 for an ~1000 US gal ones. Just need a way to get a window in. Most if them are round, which is the best shape to cope with bowing but some are rectangular, and I am not sure how much these bow - any bowing would stress the seams around the window. So, round tank+rounded, same radius window ways may be safer but, of course, they are smaller and distort the view of what's inside the tank.

Fiberglass, steel, aluminum, and any other plastic all bow too. The only non-bowing option atm is reinforced concrete.

[MatsP]

Technically, I believe concrete also bends - just that it's cheap to build very thick, because most of it is pretty low cost sand/gravel/stone mixed with a bit of cement and water. Obviously, reinforcement will add to the cost, but it's still relatively low cost.

One idea on the plastic storage containers: How about fitting a "frame" for the window (from aluminium or steel) to firm up the fitting around the window.

--
Mats

[crkinney]

Hey Victor : Back when I was a kid we use to visit an aquarium that was just a little different. It was the Miami Aquarium and it was on board an old steel hulled sailing ship called Prins Vlademar at Bayfront Park .It had large windows cut into the bulkheads and was something I have never forgotten.That was in the 1940/50.
Got an old boat?
mule

[Viktor Jarikov]

Good idea. But for now, for a far, back burner... It'd be real cool though. I can see it. In my dreams. I've read about a woman living in an old Boeing 737 or something. She bought the decommissioned plane for like $2000 and paid 20,000 to move it to her lot. My kind of gal.

Don't know what old big boats run at It'd make for an interesting, "bizzarre-reverse-world" display.

[apistomaster]

Technically, I believe concrete also bends - just that it's cheap to build very thick, because most of it is pretty low cost sand/gravel/stone mixed with a bit of cement and water. Obviously, reinforcement will add to the cost, but it's still relatively low cost.
--
Mats

The tensile strength of plain concrete is approximately 1/10 of it's compressive strength.
Our modern reinforced concrete is possible because steel and concrete have almost the same thermal coefficients.
Reinforcing steel is placed wherever the concrete structural member is subjected most to tension and/or flexural stresses.