Spaced Cowboy
08/19/2011, 05:55 PM
Hi all,
So, from what I've read, it appears to be canon that if a tank has a plastic rim, putting an expanded-polystyrene sheet between the stand and the tank is a no-no. The tank-manufacturer (glasscages) I got my tank (which has a plastic rim around the base) from, though, states "A sheet of 3/4" Styrofoam (reaching completely side-to-side and front-to-back) must be placed between the tank and the surface of the stand." (see the "warranty" (http://www.glasscages.com/?sAction=AqWarranty))
So, I got to thinking about it. The tank is 8' x 2' x 2' (a standard 240 gallon tank), and the polystyrene they supplied was ~0.5" thick. According to the calculator (http://boonedocks.net/fishtank/ftweb.php), I'll have ~3000 lbs to support on that rim.
The rim is ~1" wide, so we have approximately (96+96+24+24) square inches to support 3000 lbs, which leads to a load of ~12.5 psi. There is a table showing how expanded polystyrene deforms with load at http://www.universalconstructionfoam.com/resources/geofoam-data-sheet.php. If we take the worst-density foam (let's assume glasscages aren't supplying super-quality packaging!), then at 12.5 psi, it is quickly going to deform to where the entire base of the aquarium is supported.
So, the equation now changes, and you have (96x24) square inches supporting 3000 lbs, for a load of 1.3 psi.
Now, 1.3 psi on even the worst-density foam won't deform that foam by even 1% of its thickness. At this point, the support offered by the foam would appear to be complimentary to the entire underside of the aquarium base.
So, what's the problem with foam between the tank and the stand ? I should mention that GC seem to make their tanks (well, mine is this way, anyway) with the sides sitting on top of the base, *not* with a "floating" base between the side walls. Even with a floating base, I think the minimal deformation would make it well-supported, but with a non-floating base I really can't see why there would be a problem.
So, back to the start. Considered wisdom is that foam is a bad idea. What am I missing ?
Simon
So, from what I've read, it appears to be canon that if a tank has a plastic rim, putting an expanded-polystyrene sheet between the stand and the tank is a no-no. The tank-manufacturer (glasscages) I got my tank (which has a plastic rim around the base) from, though, states "A sheet of 3/4" Styrofoam (reaching completely side-to-side and front-to-back) must be placed between the tank and the surface of the stand." (see the "warranty" (http://www.glasscages.com/?sAction=AqWarranty))
So, I got to thinking about it. The tank is 8' x 2' x 2' (a standard 240 gallon tank), and the polystyrene they supplied was ~0.5" thick. According to the calculator (http://boonedocks.net/fishtank/ftweb.php), I'll have ~3000 lbs to support on that rim.
The rim is ~1" wide, so we have approximately (96+96+24+24) square inches to support 3000 lbs, which leads to a load of ~12.5 psi. There is a table showing how expanded polystyrene deforms with load at http://www.universalconstructionfoam.com/resources/geofoam-data-sheet.php. If we take the worst-density foam (let's assume glasscages aren't supplying super-quality packaging!), then at 12.5 psi, it is quickly going to deform to where the entire base of the aquarium is supported.
So, the equation now changes, and you have (96x24) square inches supporting 3000 lbs, for a load of 1.3 psi.
Now, 1.3 psi on even the worst-density foam won't deform that foam by even 1% of its thickness. At this point, the support offered by the foam would appear to be complimentary to the entire underside of the aquarium base.
So, what's the problem with foam between the tank and the stand ? I should mention that GC seem to make their tanks (well, mine is this way, anyway) with the sides sitting on top of the base, *not* with a "floating" base between the side walls. Even with a floating base, I think the minimal deformation would make it well-supported, but with a non-floating base I really can't see why there would be a problem.
So, back to the start. Considered wisdom is that foam is a bad idea. What am I missing ?
Simon