CO2 requirements for Low Light Plants
 

Because of the depth of my tank (30inchs) and the limited lighting
(3x25watt tubes) I've stocked the tank with plants that require
low/medium light. I've included the stock list below but am wondering
if the plants which are growing ok but slowly would benefit from the
addition of CO2, or because of the low light and there for slow
growing species I've got, do they not require much CO2. Thanks in
advance.....Darren.
Echinodorus Bleheri, Cryptocoryne Wendtii, Micosorium Pteropus,
Lobelia Cardinalis, Anubia barteri v.nana, Anubia barteri v.barteri,
Cryptocoryne pontederiifolia, Hygrophila corymbosa, Cryptocoryne
undulata(broad).