same! rep-cal makes a brand w/ d3 and w/o but miner-al-O is a great supplement for a daily dusting. you might also want to consider a multivit (made by rep-cal) to give your cham like once a month as well.
The rep-cal brand of calicum With D3 is very potent. It is the brand I use, but it should not be used more than twice a month and once a month may be sufficient. A brand like Miner-al-I could be used as much as weekly. Every brand has different ingredients, and you also have to think about the type and gender of the chameleon, what the chameleon eats (what's in the gutload and the type of bugs used), how much outdoors time it gets, the type of UVB lighting, etc.