It does look like a type of hair algae to me. And BTW hair algae LOVES water flow (probably why it grows on powerheads). That's how it gets it's nutrients.
If you can grab and pull it out like clumps of grass its a hair algae. Don't worry about the sand. A DSB
(6"+) is hazzardous, but a shallow sand bed is often stirred by may things (fish, crabs, snails). I would shut the pumps off and gently pull it out, trying not to loose any into the rocks.
If it is slimy and gooey, then it is cyano
and will need to be sucked out, but I don't think it is.