Try it out and see if it works.
This is my experience, illustrationed in the diagram below. Grey represent the sand bed. Red dots are detritus.
A gyre flow is represented in blue, which probably can only carry off the detritus at/near the surface. To effect a good cleaning of the sand bed, the current needs to flow upwards, like the green lines. That's where turkey baster/siphon comes in.
Sorry for blabbering so much on your thread. Keep the updates coming!