mechanically removing every bit if it is the best solution.
suck it out during water changes, blast it off with a power head, scrub it with a toothbrush.
get a 1 micron filter sock and place it in your sump while your return pump is on,
syphon as much as you can get, then use a power head to blast off what you missed then do a water change and repeat until its gone.
high flow helps to prevent it from latching onto your rock but high flow alone is not the answer.
maintain low nitrates and phosphates and you should be good!