Sand bacome sticky

[assafelbaz]

Hi.

I noticed that in my small tank (10 gallon) the sand in some areas become a sticky layer. If i am waving with a stick above the sand in that area it moves as a piece. I think it's made by the snails, but i am not sure.

Can someone explain?

Thanks!

 

[Mandarin66]

Any pics?

 

[sen5241b]

What kind of sand is it?