Calcium scaling will generally appear on all of the underwater surfaces rather than floating in your spa water. When it gets severe it will feel like sandpaper. However, it can sometimes also be free floating in your spa.
To test for calcium, put some of your spa water in a glass bottle and add vinegar. If the flakes dissolve and disappear, they were calcium. Please refer to “Deposits (Scaling) on your spa shell” to resolve a calcium scaling issue.
