Advice on hair colour

Raindrop32

Hi everyone I need a bit of help on a hair colour. 
For the past year I've been colouring my hair with the colour is called glacial cool brown and though it's a lovely colour to begin with I wouldnt say it's cool toned it fades quite quickly to a dark reddish colour it's also quite dark. I'm wanting to go an ash brown because I have pink skin tone so think this will look better. Would you go for a lighter ash brown or darker? I'm thinking the lighter if it was to cancel out the red as when I've previously coloured my hair it's gone more black than brown. Thankyou.