# Polystyrene curiosity.



## sectionq (Jan 27, 2015)

Hi,

just built a stand for my 150L cube(ish), anyway been trying to get it flat so that the aquarium sits making contact all around. I used a kitchen worktop cut down, it's 5 or 6 cms deep and the aquarium sits pretty flat on it. But my tank is rimless with 12mm glass and on the advice of many I then put on a 1cm sheet of polystyrene for the tank to sit on so that it can take care of any minor imperfections. Fine I thought, but then when I put the tank on it you can run a piece of card all around the outside between the polystyrene and the tank bottom. There isn't any of the tank touching around the edge and corners. All the weight is in the middle, it's the white builders polystyrene, not sure if that makes any difference but has anybody else experienced this? Without the foam it is ok and all touching, how could this be? Maybe I found a piece of foam that tapered out around the edge but I had to cut it down from a 1 metre sheet so at least one side would have been fine if that was the case. Not sure what to do, forget the polysyrene all together? Are the stories about tank bottoms failing due to a speck of sand all exaggerations?

Thanks 

Jamie


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## Tolak (Nov 13, 2012)

It sounds like a traditionally built tank, with the bottom supporting the sides. A pic would help confirm this. The stryro should be fine, while the speck of sand may be a bit of an exaggeration, a piece of gravel or other hard object that size certainly isn't.


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## sectionq (Jan 27, 2015)

Yeh, I'll post some pics up when I've finished dithering about, the original top in ply has a couple of 1/4 to 1/2mm gaps that I'll probably shim a bit to get it flat. The kitchen top was just an experiment as I knew it was flat to see if the foam was the problem or not. Anyway, you were right about the foam it has started to compress over night and at least so far there are no gaps at the back now. You can still slide a credit card along the front but you can see why now as the tank is sloping back a bit, needs lifting a couple of mms to take the weight off. 

Thanks anyway, sure this won't be the last post on this saga. 

Jamie


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## sectionq (Jan 27, 2015)

This picture I think will tell you how the stand is built, that is with about 8mm of water in it. I've taken the kitchen worktop off as that was really only to use as a reference because it was (assumed) flat. Now I'm back to my original plywood top, I've shimmed the legs and that has helped but I can still slide a sheet of paper under some of the corners as mentioned in another thread. http://www.tropicalfishkeeping.com/diy-aquarium/my-diy-aquarium-stand-top-flat-513546/#post5684154


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## sectionq (Jan 27, 2015)

Sorry, THIS picture.


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