blyxa japonica help

["Chris Ferrell" <ferrell_chris at hotmail_com>]

I've recently gotten a few good pieces of blyxa japonica to try out.  I had
some a few months ago and had no luck... they just struggled for a few weeks
(6-8) and finally died.  I'm trying to figure out some tricks.

My tank is a 20 gallon, flourite (older substrate, 1+ year), 55w PC (new),
CO2 controller @ 6.7, regular additions at weekly water changes of N, P, K
and micro.  I also dose a little bit mid-week and top off the water.
Everything else in the tank thrives (some other "difficult" plants as well).
No fish that would really attack it (platies, SAEs, ottos, smaller rainbow,
rosies)

My buddy I got the plants from has no trouble with it in several tanks, all
similar in setup (PC lighting - with much older bulbs actually) except for
the substrate.  His is sand w/ clay and some peat in the bottom layers.
That's the main difference, though dosing and water parameters might be a
little different (though we aren't that far away, so it shouldn't be that
much different).

Anyone had any experience w/ blyxa that would correlate to the granule size
of the substrate?  Anyone had luck w/ blyxa in flourite or other similar
sized (or larger) gravel?

Thanks,
Chris, in Charlotte where it's been amazingly dry for four days.