vermiculite/laterite combination?

Well I finally received my first issue of The Aquatic Gardener :-)  Very 
Exciting!! :*O
	In reading Jim Kelly's article on budget minded aquariology (word??)
he advised using a soil and vermiculite mixture; The soil for iron and other
nutrients and the vermiculite for cation exchange and increased root to 
substrate contact. Since I have already bought some laterite I am wondering 
if mixing it with vermiculite will increase it's effect?  What do people think?

					Miles Morrissey
					Easthampton, Ma