About 2 weeks ago i found these reddish brown balls with like white hairs on them floating around the tank, i thought they were brown algae but i think im wrong. ive used tetra algae control 3 times and taken out all of the gravel and boiled it along with everything else in the tank. i washed everything vigorously. but its back, AGAIN. can anyone tell me what this is? or why i have it? please!