A structured sheet cross flow media is formed with a first corrugated sheet having corrugations defining flutes angled in a first direction, a second corrugated sheet defining flutes angled in a second direction, and an interstitial planar sheet disposed between the first and second corrugated sheets. The interstitial planar sheet traps the flow of fluid or gas, such as air, entering one end of the media block within opposing flutes until the end of the interstitial sheet is reached, whereupon the fluid or gas can disperse between the intersecting flutes of the first and second sheets to provide a controlled dispersal of the fluid or gas. In one embodiment, the interstitial sheet terminates at an intermediate height in the media block to define the width of dispersion of air bubbles entering at a single source point.