# Eggcrate?



## awanderingmoose (Aug 11, 2016)

I've noticed a few folks here and elsewhere recommending "egg crate" as a base when using large, heavy rocks (or a tall rock pile), to protect the bottom glass and help prevent shifting.

Assuming one is convinced that some "padding" is necessary, my question is, why eggcrate and not pure white sheet styrofoam? Granted, styrofoam seems neither as cheap nor as easy to come by as it was in the past (I recall some years ago being able to get a "lifetime supply" for under $10), but pure styrofoam is safe enough to be used in food containers, so one presumes, safe in a tank, it pads well, and is available in different thicknesses for different applications.


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## tanker3 (May 18, 2015)

1) Egg crate sinks (or does not float).
2) Easier to cut, just clip with cutters.
3) Cheap and available--Home Depot
4) Has other uses---Keeps fishes from jumping out of an uncovered tank.


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## Aaron S (Apr 4, 2015)

Also the force balance should be better for the egg crate. The concern is that you have a rock and all the weight gets transferred to the glass through one specific point. If you have egg crate under it then that force will be transferred across the whole bottom of the egg crate because it is rigid. If you put styrofoam then as the rock squishes the styrofoam on that one spot the rest of what you cut will lift up and not really be transferring any of the force away from the point.


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## DJRansome (Oct 29, 2005)

Easier to clean. But I have been convinced by engineering types that it's false security and rocks directly on the glass is fine.


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## Aaron S (Apr 4, 2015)

Just to be clear, I am not concerned about the weight in my tanks, but it is possible that a very sharp rock in an unlucky circumstance could cause an issue. Realistically there is no problem. If you are not convinced, then watch this video ...


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## newcichlidiot (Jul 7, 2010)

Sorry, not in the eggcrate camp. Just be sure you have a solid base and put it directly on the glass, not on the substrate. Now maybe I cheated a little. As I got out my trusty angle grinder and did my best to flatten out the bottom of my rocks, giving me a nice solid platform for my rocks.

4 large rocks total about 125# in a 120.


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## LXXero (May 4, 2016)

i ended up breaking a piece of my one rock off, and super-gluing it back to itself, to make it more stable. But...i still used egg-crate. I just, i don't know, it made ME more happy, even if i don't think there's a huge risk.

I guess in my mind - it goes something like this: You got a big rock on the glass, say it gets slightly moved, shifted, whatnot, just from cleaning, jostling, whatnot. You end up putting a big scratch on the glass, no biggie, by itself one scratch, not really a problem...

Now, if that rock shifts or something bumps that scratch....well just think for a minute how glass is cut. Now, just a bump, or just a scratch, no problem, it's when these factors combine that i start getting more and more scared. I decided I didn't want to take my chances.


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## BillD (May 17, 2005)

While a falling rock might crack a bottom, the risk of point loading, if you are using gravel, is more likely. Styro can and has been used under rocks. A friend started using styro under all is large rocks after losing 2 tanks to point loads.


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## ad78 (Oct 21, 2016)

have you heard the word bouyancy.. no need to use eggcrate. i have a jumbo feller rock and i need another 2 person to put in inside due to a very large and freaking heavy on a 120gallon tank.


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