How to get the sand/dirt from the bottom of my hottub?

I'm new to the hot tub universe, and wondering what's the best way to get the sand and dirt that always seems to collect at the bottom of my tub. I know I really need to set up a little foot rinse for people to use before getting in, but alas.

I've heard stories of a big syringe type vacuum?

Wondering if there's some gizmo that people particularly recommend?

Thanks for any help.