Circulation Design - Keep Sand Down

My engineer goby is hitting my very fine sand bottom and spitting it to the surface where other fish kick it up more into the water column. So I've been contemplating different setups to help keep sand down.

Anyone have suggestions on what's worked for them? I have up to 3 fans.

Right now I'm trying two fans of equal strength at opposite sides of a rectangle tank pointed toward each other 1 inch under the surface. This allows the flow to collide right at the overflow and push the water surface over and into the overflow. This skims the top well, but creates a sort of updraft near the tank bottom (90 gallon tank). Maybe a flow that points toward the sand bed is better?

Edit:Yeah this is a better spot for the Q (sorry bout that). First I thought pump forum, but it isn't about a certain pump or fan.