Polystyrene base for giant tank

[Linkandnavi]

Hi everyone,

I've just commissioned a custom 200 US gallon tank (or close enough). 179cm length, 61cm depth, 67cm height. At that size it's impossible to find an aquarium underlay so would have to join multiple together.

Instead it was recommended to me that I get a large piece of polystyrene foam that is used in wall insulation and cut it to size, which I've done (this foam). 2.5cm depth.

The advice I've had is that it will be fine but I'm after a bit of reassurance! It's obviously very different from the rollable-material mats.

Picture below of it in situ (it'll be painted to match the wood) and a video of its "springyness" attached.

Thanks.

 

[FishHobby99]

What’s the point of aquarium underlays? All my tanks sit directly upon the surfaces.

 

[Linkandnavi]

What’s the point of aquarium underlays? All my tanks sit directly upon the surfaces.

Mainly to account for any slight discrepancies in an otherwise even surface (particularly for larger tanks). If there's any unevenness in the surface, whether a slight dip or some slightly raised point then the weight of the water volume bears down excessively on that one point and can cause the glass to crack or fail. Underlays absorb those discrepancies to provide a 100% flat surface. A lot of "package" tanks, so those with tanks and stands in one, don't have them as the glass is raised slightly off the surface by the bottom rim and have an under glass base of some kind. But most custom made tanks (in the UK anyway - and I understand it's common across Europe more than the US) require an underlay or the manufacturer's warrantee is void.

 

[Linkandnavi]

I've actually just got off the phone to my tank manufacturer and the board I'm using is the one they supply with their smaller tanks (they just can't stock the size that I need), so I'm confident with my choice

 

[FishHobby99]

Thanks, very interesting. I’ll present this info to the resident engineer in my house. However, the water lines appear flat in all my tanks. Would’t I see unevenness if the bases weren’t level?

Coincidentally enough, I‘m going to buy those same styrofoam sheets from Lowe’s soon. But for a different purpose. Researching making caves for my axotles. Commonly used for DIY 3D backgrounds as well. Haven‘t had time yet to delve deeply, but looks like they carve & stack foam sections & coat with some kind of tinted concrete.

 

[Slaphppy7]

Same stuff I use under my tanks, it will work just fine.

 

[Linkandnavi]

Thanks, very interesting. I’ll present this info to the resident engineer in my house. However, the water lines appear flat in all my tanks. Would’t I see unevenness if the bases weren’t level?

Coincidentally enough, I‘m going to buy those same styrofoam sheets from Lowe’s soon. But for a different purpose. Researching making caves for my axotles. Commonly used for DIY 3D backgrounds as well. Haven‘t had time yet to delve deeply, but looks like they carve & stack foam sections & coat with some kind of tinted concrete.

Not necessarily on the water lines. I don't mean completely flat as in horizontal. I mean flat as in smooth. Let's say there is a small stone on the surface (granted, you should be able to see a stone before you put the tank on, but exaggerating for the sake of an example). The glass in contact with that stone would be subject to excessive pressure and more liable to crack. No different in principle from walking on ice. If you walk on ice with foot coverings that cover a wide surface area, your weight is spread across that whole surface area and less likely to go through. Walk on ice in high heels and the weight is concentrated on that heel point and more likely to pierce the ice.

In my case the stand is a workbench, and the surface is made of joined timber with ever so slight ridges between them (pic below). An absorbent base in principle "fills" those gaps slightly and compresses to mean that the bottom of the glass is always consistently in contact across its entire surface area.

That's how I understand it anyway (and it makes theoretical sense to me), but ultimately I'm doing what I'm told!

 

[Linkandnavi]

Same stuff I use under my tanks, it will work just fine.

Brilliant, thanks! Always pleased to know I'm not being stupid!

 

[Linkandnavi]

Coincidentally enough, I‘m going to buy those same styrofoam sheets from Lowe’s soon. But for a different purpose. Researching making caves for my axotles. Commonly used for DIY 3D backgrounds as well. Haven‘t had time yet to delve deeply, but looks like they carve & stack foam sections & coat with some kind of tinted concrete.

Sorry, missed this bit. Hopefully you'll post the outcome? I'd be interested to see it.

 

[Slaphppy7]

Not necessarily on the water lines. I don't mean completely flat as in horizontal. I mean flat as in smooth. Let's say there is a small stone on the surface (granted, you should be able to see a stone before you put the tank on, but exaggerating for the sake of an example). The glass in contact with that stone would be subject to excessive pressure and more liable to crack. No different in principle from walking on ice. If you walk on ice with foot coverings that cover a wide surface area, your weight is spread across that whole surface area and less likely to go through. Walk on ice in high heels and the weight is concentrated on that heel point and more likely to pierce the ice.

In my case the stand is a workbench, and the surface is made of joined timber with ever so slight ridges between them (pic below). An absorbent base in principle "fills" those gaps slightly and compresses to mean that the bottom of the glass is always consistently in contact across its entire surface area.

That's how I understand it anyway (and it makes theoretical sense to me), but ultimately I'm doing what I'm told!


View attachment 148592

This is exactly correct, the foam board "forgives" and compensates for any imperfections on the stand surface

 

[Colin_T]

High density polystyrene foam is better. The foam shouldn't squish down that much.

All aquariums sold in Australia are put on polystyrene foam. It reduces the chance of the base cracking if the stand is not perfect.

Coincidentally enough, I‘m going to buy those same styrofoam sheets from Lowe’s soon. But for a different purpose. Researching making caves for my axotles. Commonly used for DIY 3D backgrounds as well. Haven‘t had time yet to delve deeply, but looks like they carve & stack foam sections & coat with some kind of tinted concrete.

Polystyrene foam floats and needs to be weighted down. You also have to be careful because they have chemicals that can leach into the water and poison the fish. Smell the foam and if it smells like chemicals, don't put it in the tank.

 

[FishHobby99]

Great idea, using a workbench for a stand.

I have 3 smaller tanks resting on the sturdy built-in drawers on one side of the room & a bigger tank on a homemade stand on opposite

side. Steel beams run under this room.

Dang! Now I understand why I crashed through the ice in my 6” stilettos!