A nicely watered leaf is not going to wrinkle when bent. Paphs are not the most interactive plant. They don't show their symptoms very readily. If it is not well watered, it may be losing water, and that might be caused by root issues. I can't say whether they are getting "enough" calcium or not because everyone's water is different. Maybe it would be better if you contact your water utility, They have reports about how much of certain minerals is in your water. I do use RO, but I do not need to. I feel I have more control over calcium/magnesium if I use RO. But I have paphs that have been getting my water for years and do not have any issues (phrags are more sensitive).