artificial plants turning brown

tank has been set up for almost two months now. i've noticed this on the plants a few weeks ago, but within the past few days it has gotten really noticable.
 
I have the same stuff (on the glass though) - hoping it goes away! (Your's and mine.) My tank's pretty new so I'm just giving it time, although I'm hoping to get some nerites and they will help take care of it.
 
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