Depende siguro sa type ng beach sand. Yung itim, "margaja" ang tawag namin sa Ilonggo, I won't recommend. It sticks to magnets and is of iron ore origin. Yung grey naman, I think that's OK, silica based siguro. What I'd look for is the white aragonite sand, tipong Boracay sand, coral based if I'm not mistaken. This has a buffering effect on the aquarium, raising your dKH, which is good especially if you keep stony corals. At mas maganda tingnan.
My opinion only, not backed by science, so take with a grain of salt. Or sand