Can i use light brown over medium reddish brown hair?

I used a bleach shampoo over colored medium brown hair, natural color is dark brown and now my hair is a reddish brown kind of brassy. I was told I should use a light ash brown with a green base to counteract the red in my hair . I also have highlights in dark blonde. Is this information correct? What developer should I use 10, 20, or 30?

Can i use light brown over medium reddish brown hair?

the ash is correct but if the highlites are very light the ash can turn them green so be very carful when applying. you might want to put a netural light brown on instead and use all over covering the hilites also then redo the hilites later. and 20 vol. hope this helps good luck