I suggest Seachem Flourish Tabs. You insert them in the substrate.

That what I use in my 100% Flourite tank.

In my high-light, CO2-injected tank, I also give the swords pieces of Jobe's
spikes, to provide nitrate and phosphate.

This doesn't seem to be necessary in my moderate-light, non-injected tank.
It's kind of overpopulated; the fish probably provide enough nitrate.


Leigh

http://www.fortunecity.com/lavender/halloween/881/