cheers guys,the rock work is in a flat flexible sheet,you then make ply formers to mould it around,so its light,durable and fairly cost effective compared to the real concrete/ fibre product....but still around $1200 for a 3m+1.6m sheet...the art is in making good shapes out of it. still gota do the water area and bottom of the enclosure...build,build,build. :bounce: