Well the project is sort of already under way, i had stuff laying around from when i was going to make a background earlier for my 6x2.5x2.5 but that never came about.
So the tank is 36gal, i got a bunch of styrofoam, watercrete concrete, colour pigments (black, brown), silicone and expandafoam.
Also got an internal filter, and a pump where i can adjust flow so i don't even need to mess around with too much in terms of adjustment.
All i really need now is to get some piping for the pump system =].
Thanks for the reply and information.
Cheers Mark~