Your tank is TOO SAFE! Yeah, I said it - it's TOO SAFE!

[Desdinova]

Overkill but only in moderation. There's another good paradox

I think the problem here is in the description, not the action. "Overkill" is a term that is used quite liberally on these forums. The fact is that you're going to have some amount of over compensation and your own interpretation of what is necessary and what is not.

Frankly, I'm not used to seeing so many haters on MFK. I can understand differing points of view and value systems, but some of these comments lack any semblance of constructiveness. I'm generally more humble than not, since I have yet to construct a monster tank. That also makes me wonder why the straw men with the insults and one-liners don't have links to their builds in their sigs...

 

[Bderick67]

See what I mean? Flame on.

What about this? How much structure is there in those wimpy pvc pipes and plastic sheeting. If that pool can hold a bunch of people bouncing around and it looks right around 36" tall why do people waaaay overbuild?

Bad example. Go to youtube, search swimming pool fail, see if you would like to have that happen in your house. People overbuild mostly because they are not professionals nor have degrees in structural engineering. When something is not well understood overkill happens. Kinda alot like the majority of filtration your see here on MFK. When in doubt, go full bore, it'll get the job done.

 

[sashimimaster]

Bad example. Go to youtube, search swimming pool fail, see if you would like to have that happen in your house. People overbuild mostly because they are not professionals nor have degrees in structural engineering. When something is not well understood overkill happens. Kinda alot like the majority of filtration your see here on MFK. When in doubt, go full bore, it'll get the job done.

Swimming pool fail is because people are bouncing around and stressing it. If the pool was not pushed, leaned on or jumped on it would not fail just from holding water. The last time I looked fish don't run into the sides of the tank just for fun. The point is you don't need overkill just to hold water.

 

[greenterra]

See what I mean? Flame on.

What about this? How much structure is there in those wimpy pvc pipes and plastic sheeting. If that pool can hold a bunch of people bouncing around and it looks right around 36" tall why do people waaaay overbuild?

View attachment 873112

I agree the stacked lumber is overkill but I also feel using pools like this as examples to show how easy it is too hold water is pretty much a poor choice. It's easy to get a round structure to hold water. Now make that structure rectangle and place a window in it and see if you can do the same thing by using the same materials?

 

[houie925]

It's a matter of comfort. some are comfortable with a safety factor of 2 and others require something in the double digits. whatever lets you sleep at night. It's not that they're too safe, just well beyond safe enough.


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[Pharaoh]

Does one hold water better then the other, no? Who cares, to each their own. If your gonna built a tank and need to feel secure with it, so what if it is overbuilt.

I agree. Although the height of the aquarium accounts for a majority of the pressure, the sides need increased support as the span (both length and bottom) increases. There are deflection factors to account for in wood and glass that you must aslo account for. It isn't merely about the water pressure; it is also about the amount of support that the material can provide.

Example. You could make a tank that is 1'x1'x4' and it may only need 1/2" glass as there is plenty of support as the span is short, but make that tank 14 feet long and 1/2" glass won't cut it.

 

[Desdinova]

I agree. Although the height of the aquarium accounts for a majority of the pressure, the sides need increased support as the span (both length and bottom) increases. There are deflection factors to account for in wood and glass that you must aslo account for. It isn't merely about the water pressure; it is also about the amount of support that the material can provide.

Example. You could make a tank that is 1'x1'x4' and it may only need 1/2" glass as there is plenty of support as the span is short, but make that tank 14 feet long and 1/2" glass won't cut it.

Certainly. I suppose I'm guilty of assumption in this case. I don't know of any places that will make sheets longer than 8 feet, so I tend to assume that this would be the max distance of a single sheet. However, I'm wrong about that. But if you decide to frame sheets of 8 feet each, this shouldn't be an issue - as far as I know. Please do correct me if I'm wrong: I'm saying that if you have an 80 foot tank with 9 vertical pillars and ten 8 foot sheets of window, then the windows wouldn't have to be thicker just because it's a long tank.

 

[coolkeith]

An 80 ft long tank would be 10 x riskier than an 8 ft tank also. I'd probably want reinforced concrete block and bulletproof acrylic for a tank that big.

 

[David R]

Totally agree most tanks are overbuilt but to be honest if i build a tank I will work out the min it needs to hold water then double it for my own piece of mind

Most glass tanks have a higher safety factor than that, even a standard 6x2x2' made from 10mm glass is 2.5, and 3.4 if 12mm glass.


I think the reason most people over-build is because it is cheap insurance. The consequences of getting it wrong are so bad that spending a bit more on extra timber, fibreglass, thicker glass etc for the sake of being able to sleep at night is well worth it. A lot of the DIY tanks I see built are first or second attempts by people who aren't structural engineers or carpenters, so when you're "guestimating" the weight/strength/specs etc, rather than calculating them accurately as an expert would if say designing a house, it makes a lot of sense to err on the side of caution.

 

[necrocanis]

Everything else said aside this is MFK!!! )V(onster fish require )V(onster builds. I have to say that with large catfish or other fish smashing into the sides that may be 3' or more in size I want my tank to be able to take a beating, not just hold water. I guess if you are keeping guppies or something small this may not matter too much, but the fish is the main factor after keeping the water in. If I know I am building a 4000 gal aquarium that houses fish that may one day be over 6' in length and over 200 lbs I will for sure over build every time. i really like this discussion though. It shows people that you can hold water without much effort. now put a 100 lbs ball of swimming muscle in there and let it run full force into the side when it gets spooked and see what happens. Keep some large 3' plus catfish and you'll know what I mean. That much fish moving fast can do some real damage. They don't call them tank busters for no reason.