It comes in 2 flavors. Outdoor is d3 free, and is just plain calcium. Indoor is very low dose(100x or less vs some high dose d3 powders) D3, and can be used exclusively till they are adults. At that point Its up to you to continue using just the in door formula every dusting, or go the normal route of plain calcium every dusting, with a high dose d3 dusting 2x a month.
I have been using indoor every dusting since the 1990's will no bad reports from the vet blood work/checkups.
Thanks guys! I've been using the miner-all indoor(2x month) and outdoor daily. What confused me was people using plain calcium without the extra minerals, while using miner all 1x a week.