Flourish Excel and Onyx

["Joe Reiter - Bigfoot" <jreiter at bigfoot_com>]

Has anyone here had any experience with Seachem's product called Flourish
Excel?  I was talking to an employee at a local fish store today, and he was
telling me it could actually be used in place of a CO2 system.  I looked it
up on Seachem's website, and they say the same.  Looks like it basically
just provides a source of carbon for the plants.  Apparently they use it in
all their plant tanks at the shop instead of CO2 systems.

Also of interest is their substrate product called Onyx.  Anyone have any
experience with it?  I seem to recall some posts going by a while back
regarding that product, but I don't recall what was said.  The local fish
store employee I talked to today loved the stuff, but said it did have some
buffering to it, so it would drive the ph up to the low to mid 7's if you
didn't actively drop the ph in some way.

Anyway, I wanted to check in with you all on these products, as I find that
this particular fish store employee sometimes gets a bit carried away when
telling you how wonderful Seachem products are.  :)
-joe