Eggcrate under rocks.

[Scribe]

So I'm seeing a bunch of people cut pieces of eggcrate the size of there rocks, and placing the rocks on top of the eggcrate. What is the reasoning? Is it simply to keep the rock off of the glass?

[aandfsoccr04]

I did it so there isnt a point of direct pressure on the glass from the rock where it has an end that comes to sharp point. I thought it just spread the weight of the rock out a little more evenly throughout the bottm glass.

[Jeremy Blaze]

Waste of time.

[Sk8r]

Prevents point load on the glass, and steadies the rock so it won't landslide. It's not a cleaning problem if you have nassarius: I've pulled it as I moved-house, and found no buildup at all. First lay down eggcrate, then the base rock, then your sand (washed!!!!!!!!!!!!!!!!!!!) then the water, then your best live rock.

[JeF4y]

Spreads the weight, but most importantly it prevents a fish or snail, etc from burrowing under the rock and creating an avalanche.

[slief]

I did it many years back to elevate my rocks from the bottom of the tank so I didnt have detritus settling down there where I could not access it. The egg crate was raised off the bottom about 1.5"-2" using PVC for legs. I also had a recirc pump that directed water flow under the egg crate so that anything that fell from the rocks was pushed out from under it by the flow. At the time I was running a bare bottom. It worked amazingly well! When I finished my aquascape, you couldnt even tell the egg crate was under the rocks and it made for some nice hiding places for fish and critters as well as made some nice looking caves.

I ended up removing it years later when I changed my aquascape but would not hesitate to do it again if I were redoing things and planning to do it based on a bare bottom.

http://i390.photobucket.com/albums/oo347/shleif/Tanks/scott06.jpg

http://i390.photobucket.com/albums/oo347/shleif/Tanks/scott09.jpg

http://i390.photobucket.com/albums/oo347/shleif/Tanks/scotttank01.jpg

[Piper27]

I stacked my rock on 3 and 4" pvc fittings so the fish had more room and flow could travel better.

[Robert62779]

I have had a goby burrow under a rock the rock shifted and killed a fish hiding in the rocks.. so there is no specific answer to do or not to do.

[Khemul]

Gives a secure base to raise up rock (for those who don't use or don't trust sand). Cheaper then using live/base rock to get elevation. You can even put plumping under the rocks.

I think burrowing fish is the biggest one though. You don't want to trust the rock on sand with them, but you also may not want to bury your rockwork under a few inches of sand. Personally I didn't bother since my diggers like to push all the sand away from the rocks anyways. But I do have to make sure all the rocks are on the glass to avoid disaster. One of my Engineer Gobies nearly committed suicide digging under a rock that couldn't have been half a pound. And that rock was touching the glass, just one side had barely enough sand under it to fit the fish. They found the one rock in the tank that was only 90% secure (since we never thought a fish would bother digging under it).