Hi reefer, other than lots of pretty orange, blue and red sponges that keep growing on my LR I have steered away from larger sponges. The tree sponges from what I read are VERY difficult to keep long term add to the fact that many are exposed to the air during collection and the damage this causes is slow to appear. I know they filter feed but not sure if jsut dosing phyto is going to be enough. Lastly many sponges exude all kinds of toxins and dying sponges can wreak havoc in a closed system. The baesnsch marine atlas I think volume 2 has a good section sponge classification, Steve Tyree wrote a book primarily on sponges I heard good things about - can get from amazon or his website. Bottom line is they are very very difficult to get a healthy specimen and to keep long term.

Also I know I've read articles by Dr. Shimek and Rob Toonen (Biogeek) which you can find on the reefs.org or reefcentral archives. If you want more specifics hit up google or reply here and I'll see what I can dig up (working 12 hour shifts on a sunday sucks but hey I've got the internet!).

-Mike