I get a special mixed grade type of sand. Once it gets covered in bacteria in a month or two, I have too much flow if it is blowing around still. Fresh sand blows around. Too fine of sand blows around. I have never found that you need so much flow that mature, mixed grain sand blows around.
I would rather than 3 inches of sand than more flow. Never seen any evidence that more flow is necessary but the anoxic bacteria, phosphate buffering, carbonate buffering and sand critters to eat ich tomonts are just too real for me.