Interesting article, good info on where silicates ect come from, but the part on "why should I add silicates?" seems (extremely) brief. He spends ages discussing the ins and outs of everything, and then says - add them.
I cant really see much point, other than to facilitate replacing your greeny covered glass with slightly more transperant browny glass. 8)
Thats it - out of a 5000+ word article.
Good read though, I like the more scientific approach to reefing,