# 55G tank 1/4" off level



## Harry Muscle (Mar 21, 2007)

I've finally moved my 55G tank to our new place and as it turns out, the only place that I can put the tank the floor is about a 1/4" off level over the 4 foot length of the tank. I have a 1/4" thick soft foam layer (high end carpet underpadding) between the tank and the stand and another layer between the stand and the floor. The stand has a completely flat bottom so it spreads the weight nicely. Obviously I would like to have the tank perfectly level, but I'm wondering if this might cause more problems with weight distibution. Because the tank has a flat bottom if I just put some shims on the lower side I will create a problem with the flat bottom, since now instead of resting flat on the floor, it will rest on just the edges with a 4 foot gap in between that isn't realy supporting weight. I though about maybe doubling up the foam on the lower side, so that I have 1/2" of foam on one side and 1/4" on the other side, but again, this would to a certain extent leave gaps where weight isn't being distrubuted. So I guess my question is, which is worse, a tank and stand that transfer weight very well to the floor but are 1/4" off level or a level tank that transfers weight well to the stand, but the stand might not be transfering weight to the best extent possible to the floor. Any input is high appreciated.

Thanks,
Harry

P.S. I should probably add that the tank is currently empty (the fish are in a rubbermaid container waiting to go in)


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## aeri (Sep 9, 2007)

what type of stand is this? metal tube or a cabinet?

if cabinet you can level the imbalances by placing the compressible pink styrofoam-type foam from home depot between the tank and the stand. i'm not sure if it'd be sturdy on a metal tube.

i generally avoid placing tanks on carpet. they move and fall over easy.


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## Harry Muscle (Mar 21, 2007)

It's a cabinet stand. The stand is actually on hardwood. The carpet underpadding that I'm referring to is what I'm using instead of the unsightly pink styrofoam. The carpet underpadding I used is black so it blends in nicely with the black stand and black tank trim. Between the tank and stand it compresses to about 1/16" of an inch, but between the stand and floor it doesn't look like it compresses at all since the bottom of the stand is totally flat so it spreads all that weight out very evenly.

Thanks,
Harry


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## PPulcher (Nov 17, 2006)

If I understand this correctly, you would be shimming the tank? Shim the cabinet instead, that way you'll have it level and flat.

**Edit** 

Oh I see now, the bottom of the cabinet is flat as well. Not sure how to proceed exactly,but I would think shimming the stand would be a better solution than trying to make up a 1/4" gap under the tank.


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## Harry Muscle (Mar 21, 2007)

OK, I guess I didn't explain things well enough. Any and all shimming would definately happen under the stand, however, my concern is that since it's a flat bottom stand, if I shim it the weight would be concetrated on the one side just where the shims are and on the other side just on the edge of the stand, since I would have a large gap in between (since the shims are raising the stand off the floor). Hope that makes more sense 

Thanks,
Harry


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## desjardo (Aug 30, 2008)

Yeah it does now. I dont think the 1/4" will shift enough weight to hurt the stand - although the one I have for my 90gal from BiG Als makes me nervous every time I walk by it.


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## PPulcher (Nov 17, 2006)

Harry, is this one of the BAs stands?

I think most of the structure is actually in the vertical pieces that make up the cabinet. The flat bottom is to provide some structure so that the vertical pieces stay that way, and also to equalize the weight transfer along the floor. I recall some people put a sheet of plywood under their tubular stands sometimes in order to equalize the weight. If you can manage it, I think a shim under the a part of the stand that corresponds with a vertical panel would probably do it. You'll get more weight pressing on that one specific part of your floor, but you'll have a level stand and the vertical panels are bearing the load.

It might also be possible to make a larger shim out of 1/4 plywood and custom shape and taper it to cover the entire area that would be lifted by smaller shims.


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## Riceburner (Mar 14, 2008)

Do not shim between the tank and stand. Shim the bottom of the stand. If it's a 1/4" off on one side, shim that side up 1/4" and shim under the stand supports with what measurement it happens to be. If it's made of 4 vertical supports, shim under those and you'll be fine. Get some wood shims and adjust as needed. The shims are wedges, 








so use 2 for each spot, thinest sides together and push together to get the right thickness.
Like this..








..'cept, flat on it's side. Shim the 1/4" end first, measure the amount that it's off under each support, cut the shims so that the thickest end is the thickness of the gap. Slide shims together and tap tight. Probably have to do the center shimming with some weight on the stand, empty tank should be enough. Doing the front is easy, the back will be a bit trickier, but finger snug should be enough.

...my 70 is almost 1/4" off on one side...I just left it.


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## pat3612 (Jan 29, 2008)

My 90 gal is off 1/4 in to its been that way for quite awhile I just left mine to.


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## Harry Muscle (Mar 21, 2007)

pat3612 said:


> My 90 gal is off 1/4 in to its been that way for quite awhile I just left mine to.


Just curious, how long is a while? Years or months?

Thanks,
Harry


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## Riceburner (Mar 14, 2008)

few months for mine...about late summer


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## Harry Muscle (Mar 21, 2007)

Thanks for everyone's comments. There seems to be some conflicting ideas (ie: fix it vs. I left it and have no problems) on unlevel tanks, so I got thinking about the actual physics involved.

So I was wondering if there are any physics buffs out there that might help me figure something out ... does an unlevel tank (that is perfectly supported from below) actually encounter any extra stresses than a level tank. I know it's generally assumed that a tank that is not level has a greater chance of cracking, but is that really the case. It's obvious that a tank that's not supported well from below has a greater chance of cracking since the weight is not being distributed properly and that put's pressure points on the glass and/or seals. However, what if the tank is supported perfectly (ie: the surface it sits on is perfectly flat), but it's slightly unlevel. Does that in reality place any extra pressure on it? If it does, how much? Physics should be able to answer this for us. 

I'm good with math and was good with physics years ago in school, but the problem I'm having is trying to figure out exactly what the logic is behind an "unlevel tank is more likely to crack". The best logic that I can come up with is that since the tank is unlevel that means that the glass panes are not vertical, so instead of just holding water in the tank (pressure along the x and y axis), there will also be a certain amount of water sitting on top of the glass (on the side of the tank that is lower) (pressure along the z axis). You might have to draw a picture to follow the previous explanation. But the amount of water is very small, for example, if a 4 foot tank (48" x 12" x 24" for example) is 1/4" unlevel from left to right, the glass panes on sides will be off from vertical by about 1/8". That means that that there will be about 18 cubic inches of water resting on the glass pane. That's 0.65 pounds of weight. I highly doubt that 0.65 pounds of water is able to increase the risk of a tank failing, or can it?

The 18 square inches of extra water adds 0.65 pounds of weight or pressure in the z direction. However, in the x direction, that same piece of glass (12" by 24" side) is already experiencing 114.37 pounds of pressure. So it's obvious that a slight unlevelness of the tank adds only a very small amount of pressure to one side. About 0.56%.

So far, what I'm seeing is that if the stand that the tank is on has any chance of warping due to being shimmed it might actually be better to leave a tank unlevel instead of risking an non flat surface developing for the tank to sit on. However, I am looking for more feedback and comments from others if possible.

So if anyone has any better ideas of why an unlevel tank is at a greater risk of failure let us know ... or maybe that's just a myth. 

Thanks,
Harry


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## Riceburner (Mar 14, 2008)

Well...

I don't think it's the glass that's at risk of cracking. It would be the seams. A 4' tank has the same glass on the sides, so the sides take less pressure? Maybe. Either way if the seams take the pressure of 4'xwhatever.... does being off vertical at the sides make them any less capable? I don't think so.


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## pat3612 (Jan 29, 2008)

Its been over a year now also it has 150 lbs of rock it.


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## PPulcher (Nov 17, 2006)

Harry, if the stand is level and plumb, I don't see how it could be warped?


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## Harry Muscle (Mar 21, 2007)

PPulcher said:


> Harry, if the stand is level and plumb, I don't see how it could be warped?


I'm guessing you are referring to this part of my post:



> So far, what I'm seeing is that if the stand that the tank is on has any chance of warping due to being shimmed it might actually be better to leave a tank unlevel instead of risking an non flat surface developing for the tank to sit on.


It's true, if the stand is level and plumb it's not warped, but that doesn't mean it won't warp. Take for example a flat bottom stand that is designed to spread it's weight across the bottom evenly. If you shim one side you have now raised the stand and left gaps (ie: it's no longer flat bottomed). It might be level and plumb now, but the weight of the tank will now push on parts of the stand that were designed to transfer loads directly to the floor below and it will start to warp it. So in such cases in might actually be safer to leave the stand unlevel and not risk any warping. If on the other hand you have a stand that has legs, then it was designed to transfer it's weight only thru those legs and you can simply shim those. In that case it's better to shim. Hope that clarifies things a bit.

Harry


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## PPulcher (Nov 17, 2006)

I understand now. Thanks, Harry. I can't add anything more to the discussion I'm afraid.


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## Riceburner (Mar 14, 2008)

if you shim under the support verticals you are shimming the "legs". The flat bottom may warp or may not, but it won't matter, the supporting "legs" will be plumb. But like I said, I left mine.


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## wtac (Mar 17, 2006)

IMHO, if the plane is perfectly flat, the stress on the seams will hold fine. If there was any torque/twist, then one will have future issues and there will be stress points at the apex/valley. I've had my 35gal reef w/~ 1/2" off level (lower in front) for ~7years w/o issues. 

To shim your pedistal style stand, as other poster has mentioned, add the shims to where the vertical supports are to properly support the weight of the aquarium.

HTH/JM2C/E


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