About a year ago i bought a very beautiful piece of driftwood for my 180 from manzman. Its 5feet long 2 feet high and 2feet wide. I soaked it for a month power washed it and paced it in the tank and it sank to the bottom within one week. Now the problem i keep getting dark brown "stuff" all over the glass and filter intakes it wipes clean easily but comes back within a few days. At first i thought it was the residue from the massivore delight so i stopped feeding it for a couple weeks and same brown stuff. Tank is not by a window so its not sunlight i run my light 6 hours a day and i do 2 water changes a week. What is this stuff is it the driftwood and how can i prevent it
