How do I clean aquarium sand?
I'm inferring that you have a gravel siphon. Take the big part of the siphon out and that will just leave you with a tube.
Start the tube just like how you would with a siphon and and hover over the sand about a inch or two.
You will suck up the debris and poop because all of it is directly on top and not in-between crevices like gravel. (unless you have a sand-stirring fish)
If you do have a sand-stirring fish, I can't help you and another member has to come and help you