I would work towards not having dead spots in your tank. I would siphon as much as possible of red slime out of your tank. If it were me I would favor the poly filter also. Polyfilter would pull the heavier stuff out. You have excessive waste for some reason. Salifert makes a Phosphate remover. I would use both Salifert phosphate remover and polyfilter. Phosphate remover would bind phospates and polyfilter would trap them. I love Poly filters for unexpected things. You can usually see the difference with polyfilter shortly after installation in my tank. The secret is moderation. Do not do water change and filter change the same day. You could stress your animals and cause amonia release building to more problems. Above has worked for me in past. I hope this helps.
Good points, everyone! I would also like to know what the algae looks like, like Stircrazy. Could you describe it for us - hair like, more like cyano, wirey? Also, where is it primarily growing? As suggested, once you determine what your water parameters are, discovering where your excess nutrients are coming from will help with your battle. Could you list out your tank for us....skimmer, flow, inhabitants....all the good stuff