Directional flow is more important than wave flow, you really should make sure there is a good directional current and add wave flow to that. A wave is directionless, a lifting ans suspending motion, if you have ever been to a big lake or the ocean and you kick up some coarse sand, the waves just wash it back and forth until it falls in roughly the same spot you kicked it up, a directional current is needed to actually transport debris to the filters.