I'm hoping that the considerable expense of dosing Excel regularly at
fairly
high rates will help with the CO2 level, and that increasing the KH will
make the CO2 more available to the plants. I'm not looking for
spectacular
plant growth, just a decent looking display that will enhance the tank and
make life more enjoyable for the fish. Thanks for your contribution to my
education.

As before, the only way to make CO2 more available to your plants is to add
CO2 to the water. You'll see people talking about maintaining CO2 levels of
between 20 & 30ppm when doing this and its quite common for aquarists to aim
for that.

That said ANY extra CO2 you add will be greatfully recieved. On on of my
tanks ( about 45 USG) I use one of those Hagen things that's supposed to be
for a 10-15G tank. It hardly raises the detectable CO2 level at all but
there is no doubt the plants appreciate it.


I've gone to the other extreme as well (25ppm) through a gas bottle system &
the plants go into what can only be described as "hypergrowth". I find it
too frenetic - stuff grows much too fast so even there I have tuned the
thing down to be only 10ppm or so.


rgds

Iain