Yes, red dragon is finiky. It will grow really nicely for a while and then all of a sudden you will either see STN or RTN. one thing I have noticed is that it doesn’t like a Alk spike. Even a small spike will trigger rtn. Now on the flip side, if you do a course correction by a water change or dosing, it does bounce back. Or if you frag the tips and start over with frags, most of the times the frags will survive.