OK - here we go:
This is a picture on March 23, you can see the lay of the land and the placement of my diffuser
http://s238.photobucket.com/albums/ff266/auntpammy/?action=view¤t=IMG_0219.jpg
This is when we knew we had a problem, a couple of weeks after this we were covered with DW
http://s238.photobucket.com/albums/ff266/auntpammy/?action=view¤t=IMG_0491.jpg
This is a few days ago, we are assuming the green streaks are algae?
http://s238.photobucket.com/albums/ff266/auntpammy/?action=view¤t=IMG_0878.jpg