Yeah.. looks like the algae on the inside of the glass is causing it to look yellowish. just clean the inside walls of the glass and do a water change and it should clear up. And i agree with dudey... a background will help prevent algae growth from that window behind the tank.
Btw... those pieces of wood you have as decor are bad ass!!
Very nice set up.
Btw... those pieces of wood you have as decor are bad ass!!