Aquascaping

[mighty mouse]

hi guys,

had a tank for a few months now, but it's pretty basic to look at,
i was thinking now the water is pretty stable and my fish are happy that i could make it a little bit more interesting for them to be in,

i currently have some gravel substrate (acid orange, very attractive) some rock and some planted bogwood in there, placed pretty erratically,

what i want to do is change the substrate and have like a sandbank that goes up one side of the rock and on top of it, as like a platform for my crabs, with the bogwood and plants 'growing over' the rock from the other side
however i'm worried that if i only use sand it'll shift and i'll lose the slope up onto, is there anything that's more stable than sand that i should use to create the contours of the scape, which i should then cover with sand, or would sand on it's own suffice?

cheers in advance

 

[waterdrop]

Some aquascapers use medium sized rocks, even moss covered rocks, to create a series of terraces that raise the sand levels prior to a boulder going more sharply up.

~~waterdrop~~