These a just merely suggestions. If I had this set up I would take out the wet dry setup/ remove all the filter floss/ bio balls slowly, and use filter socks. It will make maintence alot quicker, and will save you $$ from buying filter floss b/c you can wash and rewash the filter socks. Plus if you do this weekly your getting rid of the detrius collected before it starts to break down and cause other problems. Most people change filter floss once a month or so, others who have socks switch them out every other day or so which leads to cleaner water. Plus removing the the wet dry will free up some more room for something else.
When you do water changes take a syphon hose and suck up what detrius there is in the sump.
Where you have hair algae growing and cyano, you could manually remove the hair algae and syphon as much cyano as you can, and put a small power head in there to increase the flow in that part of the sump. Put some more crabs or snails down there until you get it under control.
Sounds like you have a pretty nice setup. I also sent you a link in a PM to help you out if you havent check out his site before. Let us know how things go and what you decide to do.
