Fundamentals Rock or sand first?

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Restarting one of my tanks, and now I’m faced with the old question: Do I add sand or rock first?

Should my rocks be touching the bottom glass and then I add sand around them? Or is it best to add my layer of sand and then add the rocks on top and press them down?


Dr. Fish
Wandering Nomad
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It’s ideal to add rock first to avoid shifting, especially if you plan on adding a sandsifting goby or jawfish down the road. But the rocks you lay on the bottom of the aquarium will need to be relatively flat, and after those are in place I would add sand before stacking rocks upwards.

Some people I know will add a sheet of eggcrate on the bottom of the tank before laying down rocks, to protect the bottom glass from a falling rock. But the argument against doing this is that the sand which gets trapped in-between the eggcrate creates a dead zone. :unsure:


New member
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Are you creating a structure or just stacking them (full disclosure I stacked)? If you're creating a structure you can get pieces from your LFS that are flat OR you can buy tile (real rock) and glue some of your rock to them (use thin super glue and some sand) to make a nice flat surface to use as your base. Good luck!


Crusty Old Salt
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I always add live sand first to set the rock on. Where I'm doing a large rock structure I'll use peices of eggcrate under the rock to help distribute the weight as well as grab the rock to keep it from shifting. I also add both live rock and dry rock at the same time. I'll always drill some of the rock to create a stabler structure with more open spaces for fish.