Soil depth want higher in the back corners coming down to a slope in the middle. Maybe a 1.50-2" dirt in the back corners coming down into maybe .5" in the middle? Then topped with sand. Will this cause any problems inside the deeper parts of the soil?
Should have no problems for the el natural
way the substrate is about 3in high.
I found putting reptile coconut bark under my dirt kept it from getting compressed by the sand, which would have lead to anaerobic condition.