This tank runs normally at 2wpg with CO2 injection (DIY, ~6-10ppm),

That is probably not enough light. High to very high light means over 3 wpg.
Possibly a lot over. And preferably CO2 closer to 25 ppm.

You've got a moderate-light tank, and probably should avoid plants like Lobelia
that need high light.


Leigh

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