Cooling water loss via valve cover

Hello together I’m just in the glamorous south of France and I found during oil level control earlier that in the area of the balance tank everything looks a little splashy, dried. Water level is still a little bit above min, but usually this is always at the seam of the tank. I never had to refill it. By the way, my mixture is reddish, which obviously is not the right one. Temperature display shows the same as always. Can this be related to the monkey heat? What to do now? Just watch? Fill up? Get a mixture of water or red again? Thank you for your help! bno