i pick it out by hand and usually that gets rid of alot, i siphon the rest, then if u wanna go crazy if u place a small powerhead at the sand to give some light dusting over the sand and rocks it will help it from coming back.
in order to get rid of it you need to figure out what the cause is! its usually caused by high nutrients like nitrates and phos... also lack of flow can help it grow but usually the nutrients are the biggest problem... do you have a skimmer? what size tank? what fish ect.. the more you tell us about your tank the easier this will be... a good place to start would be doing a larger water change and in the process remove as much by hand...usually you can just syphon it out but if you dont correct the problem itll just grow back