Azhunter..
Get that circulation up!! ( big one!) Emphasize your protein skimming and try to vacuum off the deitrus In those spots where the red algae is growing..do your water changes, maintain that water quality as best you can. If you pull it out and it stinks, it's probably cynobacteria. Again, water flow is imperative. Deitrus won't have a chance to settle anywhere with a strong enough flow in the tank. Poly - Filters, and good carbon ( seachem for instance) have also helped me in the past .. Peace