Anyone use this product? (follow up)

Hi again,
I been checking back the last few days, but never got any replies, so I apologise if Im being a pest.
My sister graduates Friday- & I want to go blonde.
I have Dyed Ruby red hair. I bought 4 boxes CLAIROL MAXI BLONDE (long hair,it says it will lighten EVEN black hair!) BUT, do I need to use a dye remover FIRST? (like Colorfix?) I really need to figure that out first; dont want to waste all this (expensive) in case I need to reomove color first. I would be Soo grateful for any opinions. Thanks everyone!
~Ivy

I would have to say yes remove the color first!!! To be honest you need a Maxi Blond plus another blond to balance it out. At least that is what I did to get out my Red