I use pool filter sand in my african tank and have yet to have any of it in my XP3 filters and they're about 4" off the tank floor. I stir the sand quite frequently and it settles pretty quickly so none gets sucked up by the intakes.
I would search around though because I've read on other forums that stingrays need specific kind of sand.
I would search around though because I've read on other forums that stingrays need specific kind of sand.