frag starting to STN

[fiorano]

awwwww i got some stn on one of my smaller frags... could it be because there is a power head aimed at it about 8 inches away??? well thats rubbish o well ill frag my... frag i guess lol.and i have another colony and a few of the types have been white but not bleached skeleton white the polyps are still extended and the rest of the colony has great color ... does anyone know what would cause that???