Not sure about what made it brown but your java moss might make a comeback. I'll also add that I actually liked the driftwood better without the moss.
29g planted - 2 juvie Keyhole Cichlids, 6 Serpaes, 1 juvie ABN Pleco
20 high planted - 1 Betta, 7 Harlequin Rasboras, Snails & Shrimp, 4 ABN fry
20 long - 1 Redclaw Crayfish & Misc Guppies
75g on the way!