Giant Hair Grass?

I have 2 groups of plants in my tank (from different sellers) that were sold to me as Giant Hairgrass. Both were labeled Eleocharis Vivipara. Initially I ordered from one, decided that the tank needed more, and saw it on sale from another seller.

Side by side they look nothing alike. The grass on the left is very fine and as it grows splits off towards the top. I don't know if my fish are pulling at it or this is just how the plant is propagating, but I keep finding small clumps with roots floating at the top and getting stuck in other plants around the tank. The plant on the right is much thicker, and seems to be propagating by spreading runners or something under the gravel, where I can see new shoots coming up an inch or two away from the main cluster of the plant.

They are both healthy, but I don't like the look of both of them together in the same tank, so at some point I will probably discard one. The question is, which one? I have no idea which one is really Giant Hairgrass or which will do better long term. Clearly both are growing alright as of now and have been in the tank about 8 weeks.

If it helps, the tank is 125 gallons, has flourite substrate, mid-level LED lighting (not sure the lumens/watts), and gets dosed with some Flourish every 2-3 weeks.