I use 1 or 2 times a week. (use Reptocal and ReptoLife) One at a time.
The theory says you should gently sprinkle the insect, but not bathing in the dust.
Calcium deficiency as the excess of it, is bad.
In a course that you make in Argentina, given by Durrell and Amphibian Ark. They explained the need for UVB light. Help like reptiles to synthesize calcium and D3. I saw videos of frogs sunning during the day (ex. Gastrotheca sp). A Ceratophrys half buried with his back on the ground surface in full sun. Perhaps when the animal is sufficient to finish completely buried.
I hope you can understand the concept.