HAIRSTYLIST !!! I NEED YOUR ADVISE

Josie

Okay so i bought the True Violet H19 from sally’s last night and the guy helping me suggested i use the 40 developer for a more vibrant color nowww my question is should i use the 40 or go buy the 30 developer because i’ve only used the 40 before once when i was like 18 and bleached and dyed my hair bright red and this time im not bleaching it just going in with the color and before i do anything i wanted to ask