Turning brown and sort of transparent sounds like it's melting and should come back eventually but amphirions suggestions sound correct and I would follow that.
Also, just wanted to comment that the "watt per gallon" rule has long been outdated, not that you would particularly know, just wanted to put that out there. Wattage is just how much electricity is being used, it doesn't necessarily mean that the light is stronger, make sense? I believe color is more important, more or less in these situations.
EDIT: also yeah, with the closer picture of the 'grassy' plant, yeah sorry that's not java moss >.< the first pictures made it look like it. However, I do not believe it is Sagittaria either which would be thicker. Looks more like Micro Sword.
Rembrandt II, Suiché
Leopards: 1:4 Hawkeye, Luna, Astrael, Dorian, Cullen
Gargoyle: Cloudjumper and Toothless