Is Cushion Under a Tank Really Mandatory?

are you talkin about a glass or an acrylic tank? with glass tanks, the actual glass doesn't touch the the surface. it's supported by the rim. load distribution isn't much of a problem unless you've got a very uneven surface.

acrylic tanks require the entire bottom pane to be supported. with acrylics, some sort of cushion helps to ensure equal load distribution.

Uneven pressure seems to be what takes out larger tanks after a while. While it may not be a big deal, once you get up to 100+ gallons that's A LOT of weight to trust to glass, silicone, and plastic. IMO, that cushion is worth while for larger tanks as a precaution. I'd rather just get the cushion first off then regret not getting it if the bottom of the tank should split a seam.

If your tank has a trim on the bottom, and your stand is not too unlevel or warped you will be fine. My 75g has nothing between it and the 2x4s of the stand

If you have an all glass rimless tank, definatly use some foam or something

It's a 55g glass. Stand's not the best, but not the worst. Particle board, pffh.

What about a sheet of polystyrene, just to be safe?

defiesexistence said:

It's a 55g glass. Stand's not the best, but not the worst. Particle board, pffh.

What about a sheet of polystyrene, just to be safe?

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Every tank should have cushion under, IMHO. Aquariums are years and years on same stands and wood warps (some more, some less) due to water, pressure and moisture. 1/2 m2 of foam for your 55g cost next to nothing so why calculate at all. Take 1/2 inch thickness

Thanks Majstor, I agree with the cushion thing now.

But what do do you all think of some 3/8 inch polystyrene?

defiesexistence said:

Thanks Majstor, I agree with the cushion thing now.

But what do do you all think of some 3/8 inch polystyrene?

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3/8 inch is about 9 mm , yes? Well i have 10 mm cushion under 110g so 9 mm will be ok.
And particle board is better option for stand than wood because it warps less

Thanks! Prompt replies too. I was also wondering, the sheet is a little too tall (maybe 2 mm) for under the tank. Should it still be fine? (It will be compressed, after all, but would this counteract the initial pressure from the water with any ill effects?)

I dont understand how can sheet be 2 mm too tall? Too tall for what?

The difference in height between the rim and the bottom glass. There's a hollow (of sorts) under the tank, caused by the rim, making space between the bottom glass and the stand. This is where I was planning on putting the polystyrene, but it's a couple mm tall for the hollow. Hope that made sense?

First questions still stand, and thanks again.

Aha, i understand. I have also one smallish aquarium with metal rim (from the 70s, silicone was not what is today so they reinforced it that way) and have gap of few mm under it due to thicker metal rim.
I was asking myself too how to handle the cushioning so i cut and put foam to fit bottom glass without rim, put some water into tank to let it sit on foam and then pushed strips of foam under metal rim (all around)

If tank has plastic trim on bottom you shouldn't need anything under tank.If you place styrofoam that is too thick it can bust the bottom glass.I would put foam under a tank with no trim.Both of my tanks 120 and 240 have a 1/2'' foam under them,they have no trim that way it helps if any part of the solid surface is not perfectly even.htp

defiesexistence said:

The difference in height between the rim and the bottom glass. There's a hollow (of sorts) under the tank, caused by the rim, making space between the bottom glass and the stand. This is where I was planning on putting the polystyrene, but it's a couple mm tall for the hollow. Hope that made sense?

First questions still stand, and thanks again.

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SNAKEMANVET said:

If tank has plastic trim on bottom you shouldn't need anything under tank.If you place styrofoam that is too thick it can bust the bottom glass.I would put foam under a tank with no trim.Both of my tanks 120 and 240 have a 1/2'' foam under them,they have no trim that way it helps if any part of the solid surface is not perfectly even.htp

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Agreed! Don't place a styrofoam sheet just under the glass inside the rim. If want to use it, make sure the rim rests on the same styrofoam sheet as well.

Wow, thanks to the three of you!

Pink polystyrene is pretty unsightly....

So if I have a level surface, I don't particularly need to bother with a support?

defiesexistence said:

The difference in height between the rim and the bottom glass. There's a hollow (of sorts) under the tank, caused by the rim, making space between the bottom glass and the stand. This is where I was planning on putting the polystyrene, but it's a couple mm tall for the hollow. Hope that made sense?

First questions still stand, and thanks again.

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Do NOT fill the cap and place pressure on the bottom pane of glass. It is not designed to rest on the bottom glass. It is designed to rest on the rim.

over_stocked said:

Do NOT fill the cap and place pressure on the bottom pane of glass. It is not designed to rest on the bottom glass. It is designed to rest on the rim.

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Every aquarium is designed to lay on its surface. It can be with or without cushion and i didnt tell him to put foam just under middle

majstor76 said:

Every aquarium is designed to lay on its surface. It can be with or without cushion and i didnt tell him to put foam just under middle

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did you notice that I did not quote you and I quoted the OP? I was replying to his post....

Rimmed aquariums have tempered, thinner bottoms than rimless aquariums. They are DESIGNED to sit on the RIM. PUSHING on that glass can easily lead to failure. The weight is meant to be carried by the rim. If you were rimless, it would be carried evenly across the bottom, but when there is a rim you can not evenly support the rim and the bottom glass. This will cause deflection and likely failure.

Her, actually, but I don't mind :icon_mrgr

Thanks for saying why, Justin. I was wondering the reasoning behind the posts. So everyone's in agreement as far as not putting foam in the middle, without it being on the rim. It's settled, then, and I'll fill as is, so long as it's level?

defiesexistence said:

Her, actually, but I don't mind :icon_mrgr

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Gomenasai, you have "sex" in your nick so i assumed you are male