ive used that sand (was the white shell kind). it took like a week before i could see through the murkiness, had huge stick like stuff in it, and altho it says 100% natural.... it actually had small chunks of garbage in it (like some sort of plastic bag chunks)? idk about the cycle because it was put into established water and six months later i still havnt put fish in... looks ok now, but i likely wouldnt use it again. good luck and best wishes with your setup.