I've got mine in a soil substrate (1 inch) topped with Flourite (1 inch) in a non-CO2 setup. It gets some Flourish Excel dosed as recommended and a weekly dose of Easylife Pro-Fito. The tank, 10 gallons, is in my balcony where it gets about 12 hours of ambient light and 16 hrs (haven't installed a timer yet, so it has to wait till I get home from work) of an 11W PL. Filtration is the smallest Eheim Liberty and the setup is about a little more then month old.
The C. tonkinensis is growing very slowly, as is most of the plants (Marsilea quadrifolia, C. wendtii 'green', C. nurii, C. griffitii, Anubias barteri var. nana and Java moss) in the tank.