How to adjust custom white balance in underwater photographs when max tint is 150?

I am having trouble using the custom WB tool on my underwater photographs because Lightroom has a maximum for the red value of tint which is 150.
I know the WB is not correct because when I import my photos to Lightroom I can see how they should be for a few seconds, before Lightroom changes the colours to all of them. I am shooting in RAW.
Why does Lightroom not keep the colours as I can see them just when I import the photos or in Finder? And how can I change the tint limitation? Or does anyone know any other program I could use better to work with my underwater photos?
