Neptune Aquatics

Tank is 1/2" Uneven

First, I didn't nail it. The professor of Physics that I went to school with (and played D&D with for years) nailed it. Second, I would still try to get one level 9and did with my new one), but I also wouldn't sweat it if it wasn't completely level.
 
I'd get it level just to make sure the overflow drains evenly :)
Forget all the math here, this whole SIP crap has me not wanting to do any physics at all except the minimum amount that's required for my job.
 
sfsuphysics said:
I'd get it level just to make sure the overflow drains evenly :)
Forget all the math here, this whole SIP crap has me not wanting to do any physics at all except the minimum amount that's required for my job.
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Hey! You're the physics dude -- why didn't you set these folks straight? :) Frankly, shims can be a "fix" that just makes the overall issue worse. Shims place uneven stress on a single point of the stand.
 
JVU said:
Yes that is the common misconception. Fluids don’t work like that though.

The force of gravity is exerted as a pressure that pushes in all directions equally for any given depth. The actual force exerted is the pressure (depth) times the surface area of the wall, without regard to which way is down. So a larger panel has more force pushing on it, but it doesn’t matter if it’s the bottom or the side at a given depth.
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THis is why tall tanks gotta be thick
 
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Thanks for the feedback everyone!

I spent a few hours today placing some think metal plate under each post the level this out (Followed by a handful of shims around the edge of the metal frame it the stand sits on). The tank is now about as close as it gets on this floor. It's off about 1/8th of an inch on the length, and about 1/16th on the width.
 

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Schmuck-Reefer said:
Thanks for the feedback everyone!

I spent a few hours today placing some think metal plate under each post the level this out (Followed by a handful of shims around the edge of the metal frame it the stand sits on). The tank is now about as close as it gets on this floor. It's off about 1/8th of an inch on the length, and about 1/16th on the width.
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Ahhhhhhh. New tank smell!
Start the journal now. It will Be cool to have it all in one place to look back on some day.
 
Bruce Spiegelman said:
Ok -- so I really need to correct something here. This idea that more pressure is exerted on the seams or glass of a slightly uneven tank isn't really true. My 6" tank was off by an inch for many years. During that time I researched the issue just to satisfy myself that there was no problem. Here's the easiest way to think of it. Water "exerts" pressure equally all around. Not more pressure on one side than the other. So even if the tank is slightly off the pressure is still the same. It doesn't exert more force on a corner. It's the same pressure pushing outward all around. Now in order to be 100% certain on this, and to explain it better than I can, I asked a college buddy who teaches Physics at the University of Texas to explain it. Here's the science:

"Pressure increases with depth, but at the same depth the pressure is the same. P = Patm + rho*g*h Atmospheric pressure is 101,300 N/m^2 Rho = density of water (1000 kg/m^3 for fresh or 1025 kg/m^3 for salt) g = gravitational constant = 9.80 m/s^2 h = depth in meters"

The pressure of an extra inch of "depth" is negligible so pressure on the 1" lower corner is the same as it is on the other corners. .
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Yes I totally agree. This is just basic high school physics.
 
JVU said:
Yes that is the common misconception. Fluids don’t work like that though.

The force of gravity is exerted as a pressure that pushes in all directions equally for any given depth. The actual force exerted is the pressure (depth) times the surface area of the wall, without regard to which way is down. So a larger panel has more force pushing on it, but it doesn’t matter if it’s the bottom or the side at a given depth.
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But...if the water is higher on the low side, than there is more pressure because the depth of the water is higher, what am I missing?
 
Wlachnit said:
But...if the water is higher on the low side, than there is more pressure because the depth of the water is higher, what am I missing?
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Yes, there would be a max of extra 0.5 inches of water pressure on the bottom of the lower side compared to the other far side, or 0.25 inches more than the average pressure at the bottom across the whole tank. So about 1% (0.25” of 24”) greater pressure at the bottom of the deepest point compared to the average bottom pressure (or the bottom of the same tank properly leveled). Not a very big difference and certainly not a dangerous difference.

I’m not sure if you are missing anything if that inconsequential 1% increase is the only issue you see. What others were saying is that the water would be leaning against the side on the lower side because of gravity, which isn’t the way it works.
 
Wlachnit said:
But...if the water is higher on the low side, than there is more pressure because the depth of the water is higher, what am I missing?
Click to expand...

What you're missing is there is no effective difference in pressure. Think of a three dimensional ball. Imagine "force coming off the ball from every point and pushing outward at equal force. It doesn't push "harder" down than up, etc so it doesn't push harder on something just because somethings an inch lower.
 
Well technically if it's off center gravity is pulling the pane of glass down in a way that it wasn't designed for, almost adding a bit of a torque at the seam... but I'm sure that's a tiny amount as well.
IMO the more important aspect, would be if the top of the tank isn't in any way covered by an overlapping canopy the water line would look off, and yeah that would bug the crap out of me, almost like having a scratch that you haven't noticed until now... then you can't unsee it.
 
Agree, level does not matter much, but flat definitely does.
And it is not uncommon to get a twist in a stand, if one corner leg is higher than the others.

I really like John's idea of a tiny bit of water in the bottom. Never heard of that before, but should work well.
 
Besides pressure, I would try to level it as much as possible... you want longevity in a big tank. With all the factors that go into tanks failing, why not give yourself the best odds towards success.





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