Looks like a good setup for neons, how big is it? It doesn't look big enough for 200 extra Neon tetras.
The plant in the middle foreground does not look aquatic to me.
Cheers,
Mike
It may look empty, but 70 is about right for a planted tank, I would only recommend you adding about 60 more at the most, or you may get some polution problems. Whatever you do add the fish a few at a time to let the filter get used to the extra bio-load. What filtration do you use?