I have a 40 gallon tank running 1 watt per gallon and some low light
plants. i'd like to see more growth with my anubias nana's & barteri's
and java ferns. i'm thinking of doing a DIY 1 liter bottle to add a
little CO2, and connecting it to the air inlet on my powerhead.

I wouldn't bother. It's not worth it, for that lighting level, with those
plants. And the fish might not like the drop in pH that comes with CO2
injection.

Anubias are slow growers no matter what you do. Java fern will always grow
slowly with only one watt per gallon. Basically, if you want fast growth, you
must provide more light. Your tank is not CO2-limited, it's light-limited.

There's nothing wrong with a low-light tank of slow-growing plants. Saves you
a lot of time on pruning and maintenance!


Leigh

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