[sasquatch]

Robert the sand bed is sitting on a glass plate, the bottom of the sand is cut off from the water going under, imagine suspending a 10 gallon aquarium 4 inches off the bottom of a 40 gallon, fill the 10 with sand, thats the dsb. the water going under the sand has no contact its just a tunnel. I thank you for the effort you have put forth to see this sometimes a concept is very hard to explain