There is a lot of paranoia of pests, and pollution, which may have some truth to it, but I started my systems with them a month or 2 before adding corals, and I credit without proof it helped build up a better , diverse eco system. It's obviously also very natural unlike the white paint chips, or powdered sugar being offered . I also think it has a more developed waste breakdown system in place then one you have to build up over time. I think it's worth the risk, but location location for getting it. I got mine on Humarock at the time. 10pm, waste deep in the ocean collecting HD buckets of sand.My first thought when I used Tropic Eden sand was, “They just scooped this up off of the beach,” plastic, sticks, and all.