Getting a millipede

[Ghost in Souls]

So guys, it is highly possible that I will be getting a giant African millipede in the upcoming month or two. I only have two questions, first one is which brand of calcium powder should I get? and second Q is do I need a heat mat on the side of the enclosure (my room temp is around 21c)?

 

[Arthroverts]

Awesome! I hope you enjoy the wonder of diplopods!
In answer to your questions, you do not need to provide extra calcium for your millipedes, as long as you provide them with enough rotting leaves and wood, and some supplemental food, such as fruits and vegetables, they will be fine. If you really want to add some for peace of mind, then I would suggest cuttlebone.
Temperature wise, I think you would want a boost of temperature to to be in the 72-78F range. However, if you do decide to use a heat mat, I would suggest turning the mat around so that the sticky part is facing away from the enclosure, so that you don't cook your millipede. Also, do not allow the substrate to dry out significantly from the heat source, or allow humidity gradients to form, as these will kill your millipede.

Hope this helps,

Arthroverts