Turbo snail burrowing in the sand?

[Shibaken3]

I recently got two turbos seen in the picture. I can see one of them burrowing and wondering if this is a normal thing to see or if it's a disease? The water is all good ph 8.4 rest is 0, temp is 77.

 

[Dan_P]

I recently got two turbos seen in the picture. I can see one of them burrowing and wondering if this is a normal thing to see or if it's a disease? The water is all good ph 8.4 rest is 0, temp is 77.

Might just have found algae on the glass below the sand.

 

[Shibaken3]

Might just have found algae on the glass below the sand.

I dont see its mouth out and moving are they like just sleeping?

 

[Dan_P]

I dont see its mouth out and moving are they like just sleeping?

Could be sleeping and under the sand would be a good hiding place in brightly lit aquarium.