I have about 100X flow.
once a week, I disturb the shallow sand bed [using a keny scrubber ... ) , and move it around, getting the trapped detritus out, which then gets skimmed out and eaten by corals (or make a turn through sump and back to DT and settle on sand bed again lol ) I usually dose Enzymes and ... right after this, Zeozym and Coral snow.
on alternative weeks when I do water changed, I siphon half the sand bed, or basically the areas where there is dirt.
I find "Wave" that mymp40s make to be "washing" the sand sort of ... and in between rocks.