130L (3') tank w/ 2 30W tubes (10,000K and 18,000K),
Not a particularly high-light tank....

Would another 30W tube help much? ( I just used a standard fluoro light bar,
whacked a frame and a u-shaped al-foil reflector around it and got some
aquarium tubes)

Do you have 10 species of plants, or 10 plants?
Both actually :-) Although I split my novazealandea, and I just got another
3 small crypts in the mail. Right now it's about 34-40% covered, but I try
to leave bare patches open for the corys and aesthetic reasons.

Cheers,
Seweryn