if you have a micron bag you can clip it to your sump and just siphon the sand into that. You might cloud the tank a little but that way will cause less issues than just trying to scoop it out, plus you can just do a regular water change after since you didn't lose any water with the removal. Then, when you add the new sand use a funnel and a length of pvc pipe to get it down to the bottom without it creating a huge mess. If you like the black look I have always gotten a lot of "oohs and aahs" from the black aragonite.