Metal stand - Gap between tank and stand!!!

  • We are currently upgrading MFK. thanks! -neo
actually the pic simply illustrates the point. it is just clearer because there is no stand underneath it. here again is the pic of my 65g doing the flashlight test.. you can see that its really no different than the cinderblock pics. just not as visually explicit.

glass tanks do not need full perimeter support.

just ask any Canadian with a big al's steel stand. because chances are, if you do the flashlight test like I have, they are all probably pretty similar. steel tubing is seldom 100% straight. so I am told.

these stands have been sold by the hundreds for 25 years up here. customer's don't come in complaining of broken/leaking tanks. trust me. I sold many myself at Big Al's :)

IMG_0011.JPG
 
the thing is, as mentioned, it doesn't matter who says what.

bottom line is MichaelAngelo has to be able to fill up the tank and sleep well at night.

if he is not comfortable with gaps, then something needs to be done.

to be totally honest, I too did research when I set up my 150g. why? because even though I knew that glass tanks did not need full perimeter support and that all my previous tanks had gaps, the thought of 150g of water in one tank freaked me out a bit.

I went over to cichidforum where there are several canadians all with steel stands and they said the same thing: stand has gaps, tank been setup forever with no issues..I quoted some passages from that board in another thread I believe..

why do you think I can sleep at night? LOL

if you read enough misinformation on the net (ie glass tanks MUST have full support, small gaps in the middle are death and will break your tank etc etc) you start to believe it...

thats what happened with me..
 
12 Volt Man;3489737; said:
the thing is, as mentioned, it doesn't matter who says what.

bottom line is MichaelAngelo has to be able to fill up the tank and sleep well at night.

if he is not comfortable with gaps, then something needs to be done.

to be totally honest, I too did research when I set up my 150g. why? because even though I knew that glass tanks did not need full perimeter support and that all my previous tanks had gaps, the thought of 150g of water in one tank freaked me out a bit.

I went over to cichidforum where there are several canadians all with steel stands and they said the same thing: stand has gaps, tank been setup forever with no issues..I quoted some passages from that board in another thread I believe..

why do you think I can sleep at night? LOL

if you read enough misinformation on the net (ie glass tanks MUST have full support, small gaps in the middle are death and will break your tank etc etc) you start to believe it...

thats what happened with me..
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That's interesting stuff.

Just out of curiosity, what is the largest tank you have seen supported that way? As was pointed out about differences between 12 vs 18 inch wide setups, is there a point that supporting the tank that way becomes unsafe?

How about when you want to pile 150lbs of rock in the middle of the tank?

Just looking at that store setup gives me the heebie-geebies.
 
is there a point that supporting the tank that way becomes unsafe?
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there is a thread over on cichlid forum where the physics of why a glass tank only needs corner support is explained.

basically, the bottom panel acts as a 'girder' and is extremely strong.

I'll see if I can find the thread and post the exact passage.

as far as the biggest tank I have seen supported that way, well, there are two Big Al's stores near me with 125g tanks set up (to demo filters) and they are both on steel stands with a visible gap in the middle. these tank have been at the stores for the last several years.

my 150g is the same way: crappy shot of the flashlight test lol

I haven't seen too many 220's or 180's setup with metal stands around my area, probably because the LFS's don't sell too many and don't have any on display setup with water. hell, my 150g had to be special ordered.

tanks over 125g seem to be pretty rare around here..

IMG_0014.JPG
 
see this link for relevant thread for this discussion:

http://www.cichlid-forum.com/phpBB/viewtopic.php?t=147550&highlight=steel

from the thread:

Glass tanks technically only need support under the corners, but the longer the tank, the more support is needed along the length of the long edge. The underglass does not need any support. The glass is double pane on the bottom for strength. The Oceanic and All-Glass 6 foot tanks'
bottoms can hold up to 10,000PSI, the 65, 75, and 90gal tanks can handle about 8000PSI.
As long as the stand is level there is no need. Foam, if misused can cause an uneven surface along the edges of the tank and so for liabilities sake, we do not recommend it.
It is sort of a "hobbyist trick" that does work if done right. We as a corporation cannot advise on correct methods of its use.

Regards,

Rob M.
Product Lines Tech. Support Dpt.
Central Aquatics
Phone: 1-800-255-4527, Ext. 1215
Fax: 1-800-398-0396
Email: rmoneyhan@central-aquatics.com
Click to expand...

basically, Aqueon/Allglass is saying don't worry about gaps as long as the corners are supported and the stand is flat and level, and they are not recommending the use of foam underneath their tanks..part of my Aqueon tank sits directly on the stand :)
 
A few gaps in the middle of a steel stand is far different than supporting a tank on the corners only. Each contact point along the frame perimeter is exerting some force; while the tank on blocks has 0 force along the 65+ inches of exposed tank bottom.
 
well, if I do the 'flashlight test' on my 150g, even though you don't see it with the naked eye, the tank is fully supported by the end foot on each side only

ie there is 4 feet of unsupported tank along the middle, although you can't see this unless you pass a light through. the only gap that is visible without a light is directly in the middle.

so, my 72" tank has 48" of unsupported bottom if you really look closely with a flashlight.

other people with metal stands say the same thing..

see another thread about the same topic (seems everyone with metal stands encounters exactly what we are talking about in this thread - problem is, few hobbyists have metal stands, so thats why people get so alarmed - they are not used to seeing this)

http://www.cichlid-forum.com/phpBB/...ays=0&postorder=asc&highlight=steel&&start=15
 
from the above thread:

Just one thing, if you theory was true, why do they design tank stands to support all four sides?

It ain't my theory, it's just what I understand to be the case. The cross members between the vertical posts on tank stands are designed to keep the stand rigid, not to support the tank.

Put it this way, the deflection modulus of steel is over three times that of glass. Any deflection in glass due to the superincumbent load (ie the weight of the water etc in the tank) creates an equal deflection in the unsupported steel cross members. The more the glass deflects the more the steel will deflect until the glass exceeds its deflection limit and fails. The steel offers no support (resistance) at all to the deformation of the glass.
It may seem counter-intuitive, but that's the way it is.
Four-point support is all that is needed for any tank of 40 gal which is what we are discussing. Much bigger tanks may require six-point support with central posts to resist glass deflection over longer spans.
I'se an engineer too.
Click to expand...

I would love to know the exact physics behind why all these not fully supported tanks don't fold and/or break like common sense says they should..(but they don't in actual fact)

but I can't seem to find any technical info out there..the above is about as close as I have found. but I will keep looking :)
 
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