This is not easy to believe but true.
Temperate :
Many
Pinguicula grow on calcareous in wild. Some that are known to grow only on acidic can also grow on calcareous media. My biggest
Pinguicula lusitanica was noted on calcareous. In this way, I follow Jurg Steiger that wrote the following remark : some
Pinguicula grow on acidic soil because no other soil is available around. He gives the exemple for
P. corsica. It is amazing to note that
P. corsica grow well also on calcareous media.
Mexican :
Many grow on gypsum that also have Calcium in his chemical component.
I use rain water to watering my plants as in France, drinkink water is full of Chlorine but if I have no stock of rain water available, I use tap water without problem.
I think that you should no mix Calcium and peat as this can produce in less than a year a mud (bacteria decomposing the organic material with the help of Calcium) like you do with your garden comopost using lime to activate and producing natural fertilizer.
Have a look in the web-site
A world of Pinguicula, it can answer some of your questions.
Eric Partrat
I hope to be clear as english is not my mother tongue.