Calcium powder, what kind is best?

I have a 5 week old eastern box turtle and I know I need to start adding calcium powder to her diet. What kind do you use? Do I get it with vitamin d added or not? Anything I should avoid?

Your tortoise should be making its own Vitamin D by being exposed to UVB light. Plain calcium powder is sufficient.

A tiny pinch sprinkled very sparsely on food 3 times a week is plenty

I use Zoo Med Repti Calcium without D3 2-3 times a week and Reptivite without D3 once a week. You only need a very light dusting to get the desired dosage. As JoesMum pointed out, vitamin D can be produced by exposure to UVB from a bulb or also from a few minutes of exposure to real unfiltered sunlight a few minutes each week. Calcium can also be supplied via high calcium foods like soldier fly larvae (Reptiworms) or hornworms.

I provide cuttlebone. All my box turtles have freely chewed on it. I dust certain feeders with repashy calcium plus.

Is there any particular cuttlebone brand that's preferred by your box turtles (I realize how silly that sounds, but I offered my box turtle cuttlebone and he looked at me like "What am I supposed to do with this?" and then promptly ignored it.