Help. Is This Dangerous?

[purple_drazi]

I'm filling my 65g tank and I can see that the water level isn't even at the top.

Here are the measurements in the four corners from the top of the tank to the top of the water:
Back left corner 6cm
Back right corner 5.5cm
Front left corner 5.7cm
Front right corner 5.3cm

The greatest difference is the front right corner which is .7cm lower than the back left corner.
The tank is sitting on a piece of 1/2" styrofoam, on a stand.

Is this .7cm difference critical? What do I do?

 

[Tolak]

I have a 65 gallon All-Glass tank, it's a well built tank. If it were out that much in my basement I wouldn't worry about it, if it started to leak it would leak on concrete. Mine's in my living room, any leakage would be costly, so it's dead level.

Best thing to do is shim the stand between the stand & floor. Wood shims used for door & window installation work well, they can be found cheap at most any home improvement store.

 

[The_Eggman_1972]

I woluld think so even the slightest knock on a uneven tank with the presure of the water shifting could cause it to split/crack.So YES level it.

 

[LiveLifeGoJump]

The tank is sitting on a piece of 1/2" styrofoam, on a stand.

Do you really need 1/2" styrofoam? I would have though it was a bit thick and could allow the tank to settle into it uneven.

As long a the top of the stand is flat, level & as big as the tank base then3-4mm would be more than enough.

What do others think?

 

[Tolak]

The tank is sitting on a piece of 1/2" styrofoam, on a stand.

Do you really need 1/2" styrofoam? I would have though it was a bit thick and could allow the tank to settle into it uneven.

As long a the top of the stand is flat, level & as big as the tank base then3-4mm would be more than enough.

What do others think?

That depends on the design of the tank. One with a floating base, such as the All-Glass design, needs no styrofoam, as the tank is supported by the edges of the side, with the bottom raised. Pressure on the bottom glass of this sort of tank will cause the bottom to crack. Styrofoam that is too thick will allow the edges to settle in, put pressure on the bottom glass, and cause problems. Some tanks are designed with the bottom touching, these are the ones that benefit from styrofoam, as it lessens the chance of a small particle of anything putting pressure on a small area of the bottom, which will cause it to crack.

All but one of my tanks are of the floating base design, and none have styrofoam. I check with a small piece of matchbook cover or other card for gaps along the perimeter. Tanks of this design are carrying 5 to 8 pounds of weight per linear inch, as long as there are no gaps longer than a couple of inches you are ok. The one tank of the other design is an old 10-gallon, with glass twice as thick as newer ones. I use this for hatching spawns, and it gets pulled off the rack every 6 weeks or so, carried to the sink, and hosed out. I use no styrofoam with this tiny beast, and it hasn't leaked yet.

 

[Nina]

If you have only just filled the tank I would just keep and eye on it.

Once the weight of the tank has settled in the styrofoam then it should even itself out.

Or if you are worried then do as Tolak suggested in his first reply.


Livelifegojump - our heavier tanks are on thicker foam to allow them to settle better and even out any imperfections in the levels

 

[Tolak]

I honestly don't think foam caused the tank to become level on it's own, all it does is even out any imperfections beneath the tank. The foam is going to compress at the same rate regardless of the tank being level or not, as the weight of the tank is pretty much evenly distributed. I could see a slight difference if you piled rock at one end only, as the weight would be a little more as rock weighs more than the water it displaces.

I'll have a chance to test this in a couple of weeks when I rearrange some tanks. I'll toss a spare on an unlevel stand with some foam, I may be wrong, but I don't see how the foam will magically make the tank level.

 

[LiveLifeGoJump]

Livelifegojump - our heavier tanks are on thicker foam to allow them to settle better and even out any imperfections in the levels

My reasoning was that the glass would only have slight imperfections & therefore a thin layer would take all these up.

Using a thicker foam may allow more settling in weaker areas of the foam (as I thought it would be difficult to guarantee even density through the thicker foam) as the foam would be supporting all the weight rather than compressing & allowing the weight to be taken on the stand.

If this is not the case then I bow to experience.

I was likening it to the founds. of a house where you dig through the softer ground to get down to the more solid sub-soil as not matter how big or thick the founds were, if they are on a softed base (top soil) then more settling in would occur (sub-soil = stand, founds = tank bottom & foam = top soil).

Perhaps my analogy was wrong which is why I asked the 2 questions in my first post.

1 Do you really need 1/2" foam?
2 What do others think?

Do others have additional comments to make, one way or the other?

 

[LiveLifeGoJump]

I honestly don't think foam caused the tank to become level on it's own, all it does is even out any imperfections beneath the tank. The foam is going to compress at the same rate regardless of the tank being level or not, as the weight of the tank is pretty much evenly distributed. I could see a slight difference if you piled rock at one end only, as the weight would be a little more as rock weighs more than the water it displaces.

I'll have a chance to test this in a couple of weeks when I rearrange some tanks. I'll toss a spare on an unlevel stand with some foam, I may be wrong, but I don't see how the foam will magically make the tank level.

You posted this as I was typing.

Not the foam will not level the tank on an uneven stand. The stand must be as level as posible. The foam is there to 'fill in the gaps' so the full length takes the weight. Now if the stand was bowed (center sagging) the tank would only be resting on each end. If it was the ends that were sagging then the tank would rock end to end. In each case the foam would take up the gap improving support (but fixing the stand would be the best option).

Yes the foam would compress at the same rate, assuming it's density was constant through it's length & width. When chipboard is manufactured it is almost impossible to maintain the same density of the material prior to compressing it so it is sanded afterwards to even it up.
Can the density be controlled when making foam?