Thanks Muddy,your link goes more into detail and I'm sure ther are many more.Both ffof and some of the promix contain mycorise which I think adds to them being such good mixes for our girls.These fungal additives have been used for many years on small a large agriculture grows,wheat ,corn,soybeans, and etc.,with great success.I'm headed out to my grow shop to pick some up and give it a shot on my current grow and my future grows.Some of it is a little spendy but they have smaller amounts that you can mix with the soil or mix with your water.Thanks for your reply.