I'm glad you changed the substrate... I bet Artemis loves burrowing in it!
I'm curious why you have such a red light? Usually a basking light is white... so it has almost full spectrum (you usually have to supplement with a separate UVB tube). The red light may provide heat, but it does not have any other light waves, so the tortoise can't really see very well... and might not be as stimulated to move around and eat?