I have been following the discussions recently on the merits of 
vermiculite and laterite. I can see some of you have really spend a lot 
of time thinking about and researching your postings. I enjoyed and 
appreciate all the technical information regarding nutrient diffusion and 
binding in the substrate.

However, I get a sense that, like a lot of the information I get about
this hobby as a relatively newcomer, the scientific foundation of some of
the points supporting either side leaves something to be desired. The best
advices I received tend to be derived from other people's experience. In
that case, I feel that when a "newbie" asks for recommendation for
substrate additives, as did a couple of people in the last two days, we
should rely more on methods which have been "proven" successful. I for one
prefer to start with more reliable setups and leave the experimentation
for you gurus unsatisfied with what I'd consider phenomenal growth.
Laterite has been shown to provide long term success, as articulated by
many people. It is really not that expensive, relative to some of the
other Dupla products <g>. And further more, we know of substantially
cheaper sources for laterite in bulk, thanks to Earl Hamilton. 

That being said, I encourage the proponents of vermiculite to continue 
your experimentation and research and keep us informed of your results. 
Until you have sustained success over, say 2-3 years, I think it is 
unfair to recommand vermiculite as a "better" substrate than laterite to 
a newbie.

Anyway, I just want to add my .02 to the "holy war" :), and make it clear 
to people just starting out that if you are confused about what substrate
to use for your first plant tank, laterite is a less risky bet than 
vermiculite, especially if you follow Earl's suggestion to obtain cheap 
laterite by the pound.

 John Y. Ching (jyching at watnow_uwaterloo.ca)    |
 Pattern Analysis and Machine Intelligence Lab	| 
 Department of Systems Design Engineering      	| 
 University of Waterloo, Canada            	|