DEAN
I used GEOsystem Gravel by Hagen for the base substrate. I got it from PJ's/Superpet in Edmonton. Then I put a thin layer of Laterite, and a layer of regular gravel(you can buy this in bulk at the LFS)was used as the top layer. I am currently running a pressurized CO2 system 2 LBs bottle. My brother sent me the system from Asia. Very happy with it. I refill it once every 4-5 weeks. I used to pay $5.00 per refill at a local welding shop, but the boys over there know me quit well by now, and they don;t charge me anymore. Thanks for the compliments
David
Fishstreet