Macroalgae - Halimeda

[slough shark]

So all of a sudden a small Macroalgae plant has been growing in my display... I did a little research and it looks like Halimeda by the pics I found on the net. As we all know the internet is right 100% of the time.
The only thing different I've been doing is bio-pellets. I added a couple of bags into a reactor last week.... Cant be causing this already, can it?
Is this an invasive algae, should I be worried......
I dont do any dosing at all......Carbon, GFO, and bio-pellets is it.
Any help would be much appreciated.
derek