Ulns

[Aquattro]

Anytime I remove a sand bed, I siphon out as much as I can with the volume of my normal water change. I do 50g changes, so I can remove a lot of sand. To feel better if you're concerned, remove half first, then next water change remove other half.
I wouldn't scoop and disturb it, just siphon directly out of the tank.

[Aquattro]

In my 180g, I replaced a third every 2 weeks. No nutrient issues at the time, so not concerned with leaving it bare, so I took out a third, replaced it. 2 weeks later, repeat, and so on