After a busy few weeks of running around, I haven't been able to spend as much time with my turtles and I notices the other day (after a day or two of the water being cloudy) that both my RES had a reddish brown ring around their mouths.
I took the whole aquarium apart, cleaned the filter out, scoured the walls, washed the gravel out, and then put everything back together. They seem perfectly normal otherwise -- eating voraciously, chasing ruby reds around the tank, and generally acting like, well, turtles.
I feel like a terrible turtle dad. I picked up some stuff from the pet store from Zoo Meds called 'Repti Turtle Sulfa Dip' (for bacterial diseases of aquatic and box turtles) and I am prepared to use it if this doesn't clear up soon... but can anyone tell me what it sounds like it may be? Or if it is anything to be worried about?
Thank you.

