Φίλε μου καλησπέρα, δεν έχω εμπειρία με χελώνες αλλά έψαξα και βρήκα αυτό....
http://www.redearslider.com/shell_conditions.html
Σε ένα σημείο γράφει για τον αποχρωματισμό του καβουκιού τα παρακάτω:
Spots that are white or discolored can either be a bacterial infection, fungus, shell rot or mineral deposits. Bacterial and fungal infections can develop from a lack of water quality and inadequate basking. They can start in one particular area and gradually spread outward. These conditions are often contagious and your turtles would require separation during treatment. While there are off the shelf treatments available, you will likely need stronger and specific prescription medication.
Mineral deposits can form if you are using hard water. The excess minerals in the water build on the outer scutes. The development would affect all areas of the shell. If that area is still hard but lighter in color, it is possible a scute is beginning to shed. An air pocket forms under a scute, usually starting at the edges and gives it a golden appearance.
Δεν ξέρω κατά πόσο έγκυρο είναι το site αλλά ρίξε μια ματιά, γράφει για διάφορα προβλήματα σχετικά με το καβούκι.