I have fine to medium course aragonite sand and also lose some while siphoning. As a result of this depletion, I've had to add more substrate once or twice. I've always used live black and white aragonite sand when setting up and adding, but since I've become more stringent with the quarantine process I wonder if adding live sand to an established system might introduce unwanted parasites/disease. Does anyone know if this is possible or true? Pardon the slightly off topic question.