Stand for large acrylic tank - Question.

[K-ROK]

I'm getting ready to build my 409gal. acrylic tank stand. When I bought the tank it was setup and running and it had a piece of approx. 1" thick Styrofoam/insulation board in between the tank and stand.

My question is this: What is the purpose of this and do I need to use it when I complete my new / taller stand?

My tank will be a room divider and I have very little room for error with the measurements. I don't know if I need the foam divider and if I do, how much will it shrink with the weight of water on top of it?

Any help or suggestions would be welcomed.

 

[letoan]

The foam is necessary to take out the pressure point cause by the unevenness on the stand's surface, unless you can build something that is completely flat

1" is probably overkill.

The last stand I built was for 240g, used 1/2" rigid foam that 1/8 smaller than the tank's perimeter. The tank was broke down 2 years after and the gap still there.

 

[Indymann99]

I used the construction insulation board from HD or Lowes. Comes in pink and blue. It doesn't compress much at all under my 120g. Think it was 1/2".

 

[uncleof6]

I'm getting ready to build my 409gal. acrylic tank stand. When I bought the tank it was setup and running and it had a piece of approx. 1" thick Styrofoam/insulation board in between the tank and stand.

My question is this: What is the purpose of this and do I need to use it when I complete my new / taller stand?

My tank will be a room divider and I have very little room for error with the measurements. I don't know if I need the foam divider and if I do, how much will it shrink with the weight of water on top of it?

Any help or suggestions would be welcomed.

The foam under an acrylic tank, does absolutely nothing, and it is not required. Acrylic does not behave in the same manner as a glass does. Glass is hard, brittle, and inflexible; acrylic is soft, and flexible. Acrylic since it is flexible, will give/conform, to the stand top and point loading; such conformation will not harm the tank.

What you do want, that is very much the same as with a rimless glass tank, is full solid bottom support. Where as, in some cases this is not required for a glass tank, (full floated bottom such as a rimmed tank, or bottom raised inside the sides,) an acrylic tank bottom will bow down (every part of an acrylic tanks bows due to water absorption on only one side of the acrylic) if not fully supported. Once the bottom bows, it cannot be placed on a flat stand and is basically useless. Solid support will prevent the bowing, foam will not prevent the bowing.

The degree of bowing will depend on a number of variables, however, the basic property that makes the acrylic bow (absorbs water) is the chief reason I recommend against using acrylic for aquariums; I find the only advantage to acrylic is weight, and the disadvantages overshadow the weight savings.

A sheet of plywood on a surrounding frame is not solid support, as the plywood will deflect. A sheet of plywood on a frame (surrounding frame with cross members) is solid support.


That said, if you have a good solidly supported base, foam is not going to hurt anything, however it is completely unnecessary.

 

[K-ROK]

Thanks everyone for the good advice and solid facts to back it up. I guess I'll go with the same sheet of foam just to be safe seeing as it was used previously.

From letoan's statement that the 1/8" gap was still there, I can also ascertain that the foam will not expand much with the full tank weight on it. I will factor in the height of the foam in my total height calculations.

Thanks again everyone!

 

[SPotter]

The foam under an acrylic tank, does absolutely nothing, and it is not required. Acrylic does not behave in the same manner as a glass does. Glass is hard, brittle, and inflexible; acrylic is soft, and flexible. Acrylic since it is flexible, will give/conform, to the stand top and point loading; such conformation will not harm the tank.

What you do want, that is very much the same as with a rimless glass tank, is full solid bottom support. Where as, in some cases this is not required for a glass tank, (full floated bottom such as a rimmed tank, or bottom raised inside the sides,) an acrylic tank bottom will bow down (every part of an acrylic tanks bows due to water absorption on only one side of the acrylic) if not fully supported. Once the bottom bows, it cannot be placed on a flat stand and is basically useless. Solid support will prevent the bowing, foam will not prevent the bowing.

The degree of bowing will depend on a number of variables, however, the basic property that makes the acrylic bow (absorbs water) is the chief reason I recommend against using acrylic for aquariums; I find the only advantage to acrylic is weight, and the disadvantages overshadow the weight savings.

A sheet of plywood on a surrounding frame is not solid support, as the plywood will deflect. A sheet of plywood on a frame (surrounding frame with cross members) is solid support.


That said, if you have a good solidly supported base, foam is not going to hurt anything, however it is completely unnecessary.

Would it be a stretch to say that if you are buying a used acrylic tank that it might not be a good idea to put it on a new stand since the tank has already conformed to the imperfections of the stand that it was previously on?

 

[K-ROK]

Would it be a stretch to say that if you are buying a used acrylic tank that it might not be a good idea to put it on a new stand since the tank has already conformed to the imperfections of the stand that it was previously on?

Interesting thought, but if I use the foam pad it should conform to it correct? I have to make a new stand that will fit where I want it to and a different height.

 

[rwb500]

i wouldn't worry about that, especially if you are gonna be using foam. if it bent to fit a stand, then it can bend back.