Rock Foundation Placement (considering home made agrocrete "tables")

[Chromis]

I'm just looking for some answers/opinions on placing rock structures...

 

My first concern is whether or not to place the rocks on the bottom with sand around them or to place them on top of the sand. If they are on the glass it could be dangerous since the weight of the rock structure could be supported by very small points of rock on glass. If I put it on top I am afraid that burrowing creatures will tunnel under them until they collapse. Any ideas here? I was considering making my own rock for the foundation (agrocrete - check garf.org). It would be a few flat peices with very short legs to create a table that stands on the bottom (I could use small egg-crate squares to place the legs on). These tables would rise up about a half inch off the sand bed creating both an interesting cave structure for hiding creatures as well as expose more sandbed area to the water. Live rock would be stacked on top of this. Thoughts on this idea?

[Jefe12234]

I've always placed my rocks directly on top of the sand. Live rock is too expensive to bury in my 4 inch sand bed. I wouldn't worry about the rocks falling over. It would take a large animal, like a burrowing jawfish, to dig holes big enough to cause rocks to fall.

 

I wouldn't worry about supporting the rock. Lotsa people just drop it in. It works fine.

 

-Chris

[ajroahkni]

Egg crate it, LR then sand.

 

The crate will provide a grid to arrange your rocks on, which will add to stability and prevent any possible hairline mishaps. Besides, asthetically, the ocean has sand arranging itself around rock and not the other way around. I think you're attention to detail would rather have this thing looking like a crosscut of the sea and not a Japanese rock garden.