Cricket Dusting????

I have always used a mixture of Rep-Cal calcium w/ vitD3 (pink label)and Rep-Cal Herptivite w/betacarotene (blue label, multi vitamin and mineral). My question is can I just use the multivitamin and mineral powder (the multi vitamin and mineral powder has calcium in it already). I only used the mixture because that was what I read was best to do (I can't remember the reasoning behind it though). I don't mind doing the mixture if it is benefical to my animals but if not then I can stop wasting my money :D Thanks for the replies!!!!

I use Sera Reptimineral for carnivorous reptiles. It is a mixture of vitamins, minerals, and calcium.

I use Miner-All. I use the yellow top, becuase my monitor doesnt get the natural sunlight, and I love the stuff. It has everything from calcium to selenium. Pretty awesome stuff!