HUKIT
Aquarium Advice Addict
It's called a blackwater environment and the tannins that leech from the driftwood will cause this brownish appearance. Eventually the driftwood will stop leeching tannins and you'll have to add peat moss to your filter.
Or you could use Azoo's black water extract, it's fairly inexpensive contains vitamins, works well, and is harmless to fish and inverts.
AZOO CORPORATION=