How to get Strawberry blonde to platinum white in one more bleach.?

Does anyone know? I had darker orange hair earlier today and I went to sallys to get quick blue bleach, which I guess I left on for 55 minutes, and after rinsing it's just a lighter orange, I used white toner and everything. Did I do something wrong? I think I should wait a bit before I try white, but does anyone have any good tips? I have about two oz of 40 developer and A LOT of 20 developer, I have some wella bleach and I really think that I want to do just one more bleach. And hope that it gets to white, help would be greatly appreciated, please and thank you!