I'm using ExoTerra calcium as my daily duster, zoomed reptivite as my multivit 2-3 times a month and nutrobal as my D3+multivit+calcium 2 times a month.
I've had no problems at all. The reptivite is a pain to get to because the container is shaped a bit annoyingly. Nutrobal was recommended by the fellow I bought my Cham off. The exo terra calcium I picked up as it was the ONLY none-multivit and D3 calcium supplement I could find. Ridiculous really, UK petshops seem to stock so little.