Doh - had forgotten which journal had that event, sorry. Hmmmm...the algae is a norm for recently upset systems, but the sponges are still unusual since they can't just soak up the usual waste products from a new or unstable system. Occurs to me now though that it could be you've got a small free-floating microbial bloom of sorts (phyto, rotifers, etc.) going on too and the sponges are feeding on that. Have you tested the water going in to make sure it's not adding any sort of nitrates/phosphates to contribute to the algae issue? If the water in is fine, then I would assume both unusual blooms will just be temporary. Of course, that doesn't mean you'll want to just wait out the algae buildup on the glass since it's always easiest to clean off as a light dusting.
