Rocks ?

[juliovideo]

I would like to know how do you make these artificial Rocks that are inside the aquarium?

What material's are nesessary and where can I buy them?

This is a picture below of the rocks...........Thanks

http://www.royal-exclusiv.de/forum/wbboard/misc2.php?action=download&attachmentid=249

http://www.royal-exclusiv.de/forum/wbboard/misc2.php?action=download&attachmentid=250



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