Sand bed science

[santeeeyyy]

I took these at night and noticed a lot of brown dirt mass underneath the black sand. What does everyone else’s sand bed look like? My other tanks has different sand bed looks as well and one with a lot of spaghetti worms

 

[Dread Pirate Dave]

Your sand is more gravel like than mine. I used the fiji pink live sand but wish I had gone with special grade. My goby and snails keep it clean though. I don't see the buildup you are seeing in yours.