Flsun QQ-S - Slight salmon skin/ghost

HiI have just an ever so slight salmon effect on one side of the machine.I have it leveled good and generally the prints are excellent in quality. Both .2 and .3 layger height.Tested 50/60/70mm/s printspeed with no visible variation in qual.I've set the acc and jerk down to a more resonable settings and there are no vibrations in the shell of the machine when printing.It has default firmware (2.0.7 i believe).I'm using a well tuned PLA at 205c/60c bed for the speeds. At 50-60 i use 200c.I wonder if anyone have tips that i can do to further calibrate the machine, or for example TL smoothers that work with the board (not sure which board as i have not opend the base up yet).Would like to avoid TL's if possible.Thanks in advance.