Rob..did you see Mrs McGreggors thread she had a plant in those big perlite balls.. I asked her what they were...they were about 3/4 inch size like they clay sort of thing, but white...if this is what you have then get your soil from the outside put it in a roasting pan and cook it in a 250 degree oven for an hour or two to sterilize it cool it down and mix it with your pearlight