The Black Blasting Sand is completely safe for aquarium. Just need to soak & rinse it few times. For red color aquascaping, I use the Flowerock Lava rock from Lowes and the Vigoro decorative lava rock from Home Depot. A big bag (0.5 cu ft) only cost $3-$4.
For light color substrate, I use the pumice soil for bonsai. The highly porous pumice is way better than the regular gravel. It has 100x more surface area to polish the water. All my plants love it. No fish, no shrimp, no snail, not even an Oto ever die from it.......Indeed, all breeding like crazy, except the Otos.