Plant turn dark green

[ct13]

Bought this plant from Far east, was bright green colour. Have it in my FGT for 3 weeks(No fert, only 2 hr sun light), also bright green colour.

I transfer to this tank last week, surprisingly seeing it turned dark green.

Anyone can advise?

Fert: twice a week.
ADA special light, green gain, pyton-git.
Seachem trace, iron & K.

3ft x 1.5ft x 1.5ft tank with 127W PL light for 10hour daily. CO2 at 2 bps(Controlled by Ph controlled). CO2 drop checker colour green (30ppm throughout the whole day).

Facing hair algae & some BBA issue.