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Author Topic: Tank not level  (Read 7725 times)
Clare
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« on: September 02, 2010, 03:01:36 AM »

So, the big house move is completed and the fish (bar one) have survived the journey and are settled back in nicely.  However, as I've mentioned elsewhere, I've noticed that the tank is not quite level in its new home (unsurprising considering none of the floors appear to be flat).  I dug the spirit level out last night and the tank is tilting ever so slightly towards the right, just by the tiniest amount.  Front to back it is level.  Do I need to worry about this and, if so, how do I go about sorting this?  MRM gave me a very condensed version in another thread but I thought I'd repost the question here since I need someone to explain the process to me in words of one syllable and explain exactly what it is I need (I'm currently at the bottom of a very steep learning cuve at the moment with regards to DIY).

I don't know if the tank stats are relevant, but here they are.  About 31g, roughly 2ft long x 1.5ft deep x 2ft high.  Its a Juwel tank and sits on the base manufactured to go with it.  Its not supported around the edges but rather on a flat surface.  Its been a while since I've seen the stand without the tank on it but if I recall correctly the stand surface has black plastic strips across the width of it.

Thanks for any help you guys can give.
Clare
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Belinda
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« Reply #1 on: September 02, 2010, 08:49:02 AM »

Having the tank level is very important...more so with larger tanks..
Over time there will be more stress on one side and it can create a weak spot in the tank.
Level the stand and the tank will be level..the tank has to sit on the stand the way it was designed to..
Just use a thin strip of wood about 1/8th to 1/4 inch thick.
Place it under the right side of the bottom of the stand ..the whole edge of the stand should have a solid piece under it.If you have to add another strip under it.
Check with the level to see if it is enough....sometimes one corner has to be raised a touch more than the other.to keep it level front to back ..

Maybe a pic will explain better... here is what I had to do with one side of one of my stands to get it level .


* IMG_2270.jpg (66 KB, 562x600 - viewed 462 times.)
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Clare
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« Reply #2 on: September 02, 2010, 09:24:44 AM »

Thanks Belinda - from that I'm going to assume that I can just pop a bit a plywood under there to bring it back into line and there's not other issues I need to be aware of.   Smiley
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Tiktaalik Owner
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« Reply #3 on: September 03, 2010, 09:37:07 AM »

This is the worst subject in the history of the universe! When I noticed my 4' 90 g was about 1/16" unlevel I did some perusing. I'm now certain of one thing. In the immortal words of Socrates: "All I know is that I know nothing." The following posts are copied from another forum. I offer them as food for thought:

Quote
Tanks don't need to be level. I make the following assumptions that can be verified by any physics book.

1. The pressure exerted by a liquid on a container's walls is equal in all directions at any given distance from the surface of the liquid.

2. The maximum pressure in a liquid filled container occurs at the bottom of the container

3. The depth of the liquid in a rectangular container will be maximized when the bottom is level with the surface of the liquid and the container filled to just shy of overflowing.

It follows that if a container is tilted such that the bottom of the container is not level with the surface of the liquid some portion of the container is unused as the liquid will spill out of the low side of the container before the container can be completely filled. The actual pressure at the bottom of the container is somewhat less than the pressure of a level container completely filled. Because the pressure is equal in all directions that means that the pressure can't be described as pushing down on the glass, rather it is pushing perpendicular to the wall of the container at any point, if you turn that container in any direction the direction of the force remains the same. I assume that any aquarium is capable of holding water indefinitely when perfectly level and filled to overflowing, this is when the maximum amount of stress would be seen at the bottom of the aquarium. Tilting the aquarium slightly would reduce the depth of the water and reduce the pressure, if the aquarium was designed to hold water with more pressure it won't break with less pressure.

I've been through this before and I already know there are a million websites that say an aquarium needs to be perfectly level. Go ask one of your professors how you would calculate the pressure on a container holding a liquid, then ask him what happens when the container is tilted, walk through the calculations yourself and come back and show me how you arrive at the conclusion that there is more stress on an aquarium that isn't perfectly level. Honestly I'd like to know, I've got an engineering degree and this is one of those things that no professor or text book could help me understand.

The model is accurate, the maximum pressure is on the seams at the bottom of an aquarium with the maximum height of water above the seam, see statement #1, it says exactly what you do about pressure being related to water depth. The maximum water height occurs when the tank is level, if the tank is not level the maximum water height is decreased which decreases the pressure on the seams. All vertical seams have a pressure gradient from zero at the water line increasing to a maximum at the bottom of the seam, these seams don't have any trouble resisting the unequal pressure. Again the largest gradient occurs when the water height is maximized as in a perfectly level aquarium, tipping the aquarium will reduce the water height and decrease the maximum pressure at the bottom of the seam.

I graduated 5 years ago, it's been a while since I've been close to anyone in the academic community who might be able to give me some additional insight as to why a level container sees less stress. The basic assumption I make is that unequal pressures are always present on vertical seams and they will withstand the pressure gradient without incident for 10 or more years, the seams at the bottom should be no less capable of carrying a load that is unequal especially considering the net impact of a reduced water height potential of a tank that is not level. The difference in pressure from one end of an aquarium to the other in an aquarium that has 1" drop over 48" would be equal to one inch of water or .03612 PSI (1 inch water = 3.612x10^-2 PSI at sea level) a fairly negligible amount of pressure. A water balloon with a latex wall of only a few thousandths of an inch thick will easily contain that amount of pressure without rupture. In my years of keeping fish I've never had a tank leak at the seams on the bottom where the maximum pressure is experienced, I've always had leaks somewhere in a vertical seam, every leak I've had was somewhere 3-6 inches from the bottom.

This one also got me thinking:

Quote
Please, everyone who wants to think about this problem read up on hydrostatics. Regular statics does not apply to liquid and gases.

The force on a surface of a liquid filled container is a function of the liquid density, gravity, and height of the water column. This is consistent with solid statics. However, the difference is not in the equation but in the force vector. The force of a liquid is not unidirectional with gravity, but it is omnidirectional. The force of the liquid on the container is applied in all directions equally.

Because the force is applied equally in all direction, there cannot be an imbalance of the force applied on the container. In other words you can not have "more" force applied to the side if the tank is off level.


Finally, I've read dire warnings that shimming is not to be undertaken lightly:

Quote
If you do decide to shim it, the shims need to be the length of the side you're trying to level tapered over that length. If you're doing the long side of the tank you need to do both front and back and the shims need to be the same size. If you're trying to do front to back you have to do both ends and the shims need to be the same size. You can't just stick a shim under the stand at one spot. It puts undue pressure on the tank and stand and could crack the glass.

I called two reputable LFS to see if there was a consensus. #1) Incredulously: “1/16 of an inch? A ½ is okay. You’ll never get it perfect. As long as it’s sitting solid on a stand.”

#2) “Start worrying at a ¼ inch, definitely ½.”

The best thing about having a level tank is never having to think about any of this.
 
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MRM
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« Reply #4 on: September 03, 2010, 01:34:26 PM »

My head hurts now.
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GeezerSteve
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« Reply #5 on: September 03, 2010, 02:09:34 PM »

Yeah, my head hurts as well.

Ok, he's saying that in a tank that is tilted, the pressure against the sides & bottom are the same in the shallow end as in the deep end? Sorry, I'm not buying it.

The thing  here is how much of a tilt are we talking about?  Personally I would go with what the people at the LFS's said. They may not have an engineering  degree, but they have experience. Anyway, it just looks bad to have a tank that is tilted very far.   happy

"The best thing about having a level tank is never having to think about any of this."

There ya go.   confused



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gomezaddams
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« Reply #6 on: September 03, 2010, 02:14:44 PM »

Correct but not right!
its very important for any uprights in a tank stand to be perpindicular to level.Im not going to get into the multiplication of force sideways if they are not.We got some college students,someone calculate the lateral force for a 125g tank that stand upright is 2deg off perpindicular. lol

Its important for the uprights to be perpendicular to the top.for the same reason as above.
its very important that the surface the tank sits on be flat.
Add all these factors together and a well constructed stand will have all right angles at the corners a flat top and should be shimmed level.
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dang
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« Reply #7 on: September 03, 2010, 09:43:28 PM »

  All that is true, but kind of beside the point.

  I think the biggest problem with unlevel tanks is that it tends to bend the glass.  Glass doesn't have much strength to resist a bending pressure.  If one corner is lower than the rest, the glass is going to break eventually.
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dylandrewsdad
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« Reply #8 on: September 03, 2010, 10:43:39 PM »

Ummmmm....not to rain on anyones parade, but really a 1/16 of an inch? You guys would worry about that? I don't want to get into this too much, but how was that measured? Is it really a 16th, or more like a 32nd? And even if it was a 16th, I don't think it is worth worrying about.
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55 Gallon Planted tank
 2 Juvie Silver and Black Vail Tail
 1 Sunset Angel
 1 Black Angel
 2 Koi Angels
 2 Punctatus Cory Cat
 1 Clown Pleco
    
12 Gallon tank
5 Neon's
1 Adult Platy
5 Platy Fry

37 Gallon Planted community tank
2 Platy's
1 Bala Shark
1 Pleco
2 Burmese Border Loac
dang
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« Reply #9 on: September 03, 2010, 11:11:11 PM »

  Forcing the glass to bend 1/16 of an inch may not cause any problems, but I for one always try to err on the side of caution.  (as would most people who have had tanks break)
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dylandrewsdad
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« Reply #10 on: September 03, 2010, 11:16:24 PM »

Good point, guess who will be getting the level out in the AM! I am not saying I will be doing anything about it, but now I am curious! How many tanks have you had break Dang?
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55 Gallon Planted tank
 2 Juvie Silver and Black Vail Tail
 1 Sunset Angel
 1 Black Angel
 2 Koi Angels
 2 Punctatus Cory Cat
 1 Clown Pleco
    
12 Gallon tank
5 Neon's
1 Adult Platy
5 Platy Fry

37 Gallon Planted community tank
2 Platy's
1 Bala Shark
1 Pleco
2 Burmese Border Loac
Belinda
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« Reply #11 on: September 03, 2010, 11:22:58 PM »

No matter what size of tank that i use I always have a plumb line, a long level and a carpenter's square on hand..
if it is not right I will notice it and it will bug me until I am sure that it is right..
I have heard too many horror stories to be casual about a tank being level and plumb.
Have you ever seen a glass just walk itself off of the edge of a table when a heavy footed person walks by??? imagine the same thing with a leaning tank...
1/8 of an inch I check to see if it is just the trim that is crooked.. Wink
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It took 7 days for God to create this world...
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dang
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« Reply #12 on: September 03, 2010, 11:31:22 PM »

  Hard to remember them all.
  The most memorable one was when I pulled a blown buss fuse out of the fuse box and threw it and a pair of channel locks through the side of a 29G beside me.  The fuse box was toast so I picked the fish up off of the floor by flashlight.  At the time a had over a hundred tanks running.  And it took 3 days to get the fuse box replaced.  Very few losses though, thanks to a lot of water changes done by flashlight. (my wife was a little unhappy with me. lol)
  But probably only 2 or 3, spontaneous cracks for various reasons.
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dylandrewsdad
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« Reply #13 on: September 03, 2010, 11:38:47 PM »

WOW 100 tanks running! All for fun or for $$$?

My LFS has about 80 or so in the store and the owner who lives in the house behind the shop has about 80 in the house to breed. If I come in and want something I don't see, he usually has it at home! I only have 3 running now with a fourth, hopefully running this weekend! My boys want to breed fish. I told them we will start with Guppies or Moons for a while! My 8 year old wants me to breed discus! I don't think I have ever leveled a tank.......I will start checking though!
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55 Gallon Planted tank
 2 Juvie Silver and Black Vail Tail
 1 Sunset Angel
 1 Black Angel
 2 Koi Angels
 2 Punctatus Cory Cat
 1 Clown Pleco
    
12 Gallon tank
5 Neon's
1 Adult Platy
5 Platy Fry

37 Gallon Planted community tank
2 Platy's
1 Bala Shark
1 Pleco
2 Burmese Border Loac
dang
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« Reply #14 on: September 03, 2010, 11:48:09 PM »

  It was for fun.  I believe that was before I had my shop.
  It is difficult to make much money breeding fish at home, but with a little effort, you can pay for your supplies.
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PuntiusFanaticoma
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« Reply #15 on: September 04, 2010, 03:50:43 AM »

100 tanks? How many did you squeeze under your pillow, dang?
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Tiktaalik Owner
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« Reply #16 on: September 04, 2010, 04:42:42 AM »

Quote
Ummmmm....not to rain on anyones parade, but really a 1/16 of an inch? You guys would worry about that? I don't want to get into this too much, but how was that measured? Is it really a 16th, or more like a 32nd? And even if it was a 16th, I don't think it is worth worrying about.

The worrying has ceased. happy The first time I filled it I noticed that water touched one side of the black trim before touching the other. I measured the discrepancy and assumed it was negligible -- until I consulted that infernal tool of the devil, Google. Many posts maintain that anything shy of absolutely level will result in a Poseidon Adventure. Then an engineer or physicist chimes in. I found the debate to be nothing short of fascinating. Lacking the requisite background, I am unable to adjudicate it. I forgot to add this post:

Quote
I wouldn't worry about it, unless it bothers you visually. I have done some hydrostatic calculations on just this subject. The forces to the side do not become significant unless the tank is significantly off-level - at least an inch over a 48 inch run - more for a 72 inch tank. I rember a post several monhs ago where the poster said that his 90 gal was 2 inches off level. I ran the calculations and determined that the added force on the side of the tank was around 30 lbs. Even this is not a huge amount, but might be enough to cause problems over the long term.

For those mathematically inclined, the added force on the side of the tank is proportional to the sine of the angle that the base of the tank makes with the horizontal. If the angle is 0 degrees (level), the sine is equal to 0, and there is no added force. As the angle increases, the force increases. You didn't specify your tank size, but for a 90 gallon tank, You have about 720 pounds of water. If you are 1/8 inch off-level, the angle with the horizontal is 0.1492 degrees. The sine of 0.1492 is 0.0026. The component of the weight of the water acting on the side of the tank is about 1.9 pounds. This is insignificant.

For a 90 gal tank that is 1/2 inch off-level, the added force on the side is about 7.5 pounds. This is still pretty insignificant.

For comparison, the total force on both sides of the tank by the water when the tank is level is about 190 pounds (I wont go into the calculation for this because it is a little more complicated). Therefore, the additional force exerted because of the tilt represents about a 1% increase in the case of a 1/8 inch tilt, and about a 4% increase with a 1/2 inch tilt. Both of which should be acceptable.

Isn't this incompatible with what I quoted in my first post? If the force of water is OMNIdirectional, it doesn't pick the low side of a tank and wail on it; it presses out evenly in all directions regardless of the angle. I'm going back to school for my Ph.D just to get to the bottom of this #%&* issue once and for all!

The one thing I always read is that you have to avoid The Twist, where your tank is unlevel side to side AND back to front. (Now watch: an engineer or physicist will post to say this isn't anything to worry about.)
--------------------------------------------------

dang, How long would it take to breed miniature Oscars (one that gets about 8")? I don't think it would effect their popularity. Look at mini Dachshunds: they've all but replaced the full size. And it would alleviate most of the abuse. This will help pay for my doctoral studies in math & physics.
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dylandrewsdad
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« Reply #17 on: September 04, 2010, 08:24:52 AM »

@Dang-not sure we would do it to make money, just for the kids (8-11) to have a good project. If we get too many I have plenty of fish that wouldn't mind a fresh meal! (sshhhhhh don't tell the kids)

@T-If can give some advide-stop using Google! LOL
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55 Gallon Planted tank
 2 Juvie Silver and Black Vail Tail
 1 Sunset Angel
 1 Black Angel
 2 Koi Angels
 2 Punctatus Cory Cat
 1 Clown Pleco
    
12 Gallon tank
5 Neon's
1 Adult Platy
5 Platy Fry

37 Gallon Planted community tank
2 Platy's
1 Bala Shark
1 Pleco
2 Burmese Border Loac
dang
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« Reply #18 on: September 04, 2010, 02:54:32 PM »

  Tiktaalik, That would be a really neat project, but it could take a lifetime, and LOT of big tanks.  And about a year after you sold the first ones, they would be available everywhere.

  Drylandrewsdad, That shouldn't be too hard.  Many commonly kept aquarium fish will spawn if cared for properly, with no special treatment.  As is mentioned in other threads, the egg scatterers are a little tougher to raise.  (the eggs get eaten)

  To get back on topic, I think it is a good idea to get your tanks as level as possible, without being fanatical about it.  That 1/16" mentioned earlier is probably unlikely to cause any problems, but everyone has their own tolerance level for worry, so if it doesn't bother you...
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Clare
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« Reply #19 on: September 06, 2010, 02:11:32 AM »

Wow! Now I'm confused and don't know what to do.  I actually noticed over the weekend that the stand has feet.  I wonder if they're adjustable.......
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PuntiusFanaticoma
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« Reply #20 on: September 06, 2010, 02:16:44 AM »

If you are worried, why don't you just put a block of wood under the legs to make them even. Better yet, a tile piece.
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Belinda
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« Reply #21 on: September 06, 2010, 07:23:56 AM »

Tile cracks..
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PuntiusFanaticoma
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« Reply #22 on: September 06, 2010, 07:34:31 AM »

I should be a jerk and say: Oh, I meant a tile made of indestructable material, like Chuck Norris's skin.....nah, not my style.

Sorry, Clare, and thanks Belinda.
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Clare
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« Reply #23 on: September 06, 2010, 08:13:52 AM »

If those feet aren't adjustable, which they most likely aren't, I'm going to stick some wood under them.  I just need to capture the fish, empty the tank, move the tank (most likely with the neons still in it since they are impossible to catch), and figure out how thick the wood needs to be and where to get it from.  Not much really!  We tore a lot of the woodwork out of the no-longer pink bedroom this weekend and I was hoping there would be something usable amongst that lot but no such luck.  On our next weekly trip out to the DIY store this weekend I'm going to try and get some plywood.  It will give my husband something to do next weekend when he gets bored of sanding the walls!
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PuntiusFanaticoma
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« Reply #24 on: September 06, 2010, 08:21:43 AM »

If a fish is giving you a hard time catching it, chase it into the net instead.
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