"James M K" wrote in message
. ..
I have 35 GAL, half of it castles (decoration) and other halfe some stones
and wood. I want to put some plants. How much I can plant without using
CO2
injection? I suppose my fish will make some CO2.

some equates to almost nothing, unless you're heavily stocked, then you've
got other problems...

and there isnt' a simple answer to you question.. it would depend on what
type of plants you use... stem, bunch, rooted, different plants produce more
or less O2, and take different amounts of CO2 out of the water...