I've experimented on my java fern:
1) three big clumps in Discus tank with the glowlux light - been there roughly 3 or 4weeks now, 5 new bright green small leaves.
2) one big clump in unlit soon-to-be Angel display tank (once I've bought a light for the fittings and red/dark substrate) - been there same amount of time as above, no new leaves but plant hasn't deteriorated either. hopefully once I get a light tube it'll progress like the other tank.
Is HaNs still on this forum?