I dont live to far from you (around SW Hwy & Ridgeland) I gave up on my setup after battling the brown algae for 3 years. I have a friend that lives in Palos Hts. he had the same issue till he started buying his water.
I think it is something with the water supply and have heard it from others as well. I get brown slime in the toliet if it doesnt get used for a few days. I have a 6 stage RO/DI setup, tried halides, T5s, more light less light, this additive, that additive, water changes several times a week, etc, etc.
I had several different LFS test the water for and all parameters came back pointed that I shouldnt behaving any issues, nobody couldnt give me an answer.
I said enough was enough and took it down. If I get into reefs again, I will send my water supply off to lab to see what is in it to cause the issue.