1 leo will be comfortable in a 10 gallon tank with a screen lid but no smaller than that!!! If anything, bigger is better. The best substrate to use would be something that cannot be eaten like paper towels, repti-carpet, thin slate pieces, or decorative tiles. I personally find sand very risky, messy even though it does look nice (the decorative tiles you can find for floors looks even nicer though and they are safe). I have found that the best way to heat a leo's terrarium is with an undertank heat pad (UTH) made specifically for reptiles. Make sure you follow the directions carefully and buy a temp control device (a rheostat or thermostat) to keep it from becoming too hot. Don't forget to buy a wall mountd thermometer for the ambient air temp. You will need four accessories for your leo's tank: a water dish, a food/supplement dish, and two hides. The dry hide can be anything that provides the leo some cover (a plastic log or cave hide from the petstore is fine)...place this and the water dish on the cool side of the tank. Create a humid hide by cutting a door in a coolwhip container (or something like it) and fill it with damp paper towels, Bed a Beast, or some other bedding that reptains moisture well but doesn't get soggy. Put this over the place where the UTH is. You will need a supplement for your leo and I highly suggest using Miner-all (just put a bit in the supplement dish and keep it there). Pics to come of my setups!!!!!
Cleo
1:1 leos (6 eggs cooking) 