Onyx Experience and Opinions Wanted

["" <dstall at woh_rr.com>]

As a long time lurker of the list, I would first like to extend my thanks to those on the 
list here for being such a wonderful resource ....

I have a 75g tank, fairly heavily planted with 160W of flourescent lighting, DIY CO2, 
and a gravel substrate that is much too large (the gravel diameter is very large, 
leaving too many places for decaying matter as well as making the planting of stem 
plants a real chore).  This tank has been going through cycle after cycle of BGA 
outbreaks as well (eight months and counting), and I have had enough :-)  Because 
this tank is in poorer shape than my other three tanks, I have decided now would be 
an excellent time to get rid of my problematic substrate.  I have sand substrates in 
my other three tanks (pool filter sand with nylons filled with peat moss underneath) 
and I really like the ease when doing water changes.  For this reason, the SeaChem 
Onyx sand looks like a no-brainer for this tank, but I have seen such wildly differing 
opinions on it, I was hoping those here on the last that have tried it might have 
some input.  I know Tom Barr likes it, and that is enough to convince me 99%, but 
other inputs would be most appreciated as well.  Of particular concern to me is that 
the literature speaks of a "slight buffering effect", and as I only use DIY CO2 I am 
hoping to not raise the pH much over what my tanks tend to run at normally 
(pH=7.4, KH=3, GH=10).

Also, if there are any tips on washing/preparing the Onyx before placing it in the 
tank, that would be a great help as well.

Much thanks in advance,

David Stall