For color cast removal I use a three step process.
Step One is to use the Curves tool and a threshold layer to determine my White Point which I mark with the Color Picker.
Step Two is to determine and mark the Black Point just like I did the White Point.
Step Three is using a 50% Grey Fill layer to determine my Mid-tones Point.
It's more involved but since it uses a White Point, a Black Point and Mid-Tones Point, the corrections are very accurate.