Biggest problem is probabe "ditto"...pool water likely has enough chlorine to actually bleach the color.
You could try the normal fix for a water spot, just to see if that tones it down a little.
There are plenty of past posts on this subject.
What I do is..
1. Use a liquid carpet cleaner, very diluted, and
wash the whole section. Toning down a water spot requires blending into the whole section. You cannot simply treat one small spot and get an acceptablle result.
2. Then after that dries mostly, I place old sheets around the seat back and console, isolating the section to be cleaned; and spray a foam carpet and upholstery cleaner.....letting it dry; then vacuum all the dust away.
3. Maybe even rub that whole section again with a "damp" rag if the spot is still easily visible.
Granted, I've only had water spots to deal with. But, it has worked for me!
