The last couple of days, this tank has been driving me crazy! Suddenly there have been micro bubbles, then this brown dust has moved in... not sure what's going on since everything has been working just fine. I posted my tank with the DAS filtration design earlier this month. I am taking my water in tomorrow for testing since I am out of my own stuff. I thought that I would post now, just in case someone has some answers or what I may need to pickup at the LFS. I was already planning on getting some phos-zorb, but what else??