Platies do best with a quality flake food and freezedried bloodworms. Corys do best with a quality flake food, bloodworms, frozen shrimp/plankton, algae wafers and shrimp pellets (your platies will eat the frozen stuff, too.
I've never heard of "kwik" food. Nothing on google either. I'd probably be wary of that unless you have other sources telling you it's quality stuff.
I purchase my dried foods from Kensfish.com. He has high quality stuff. In fact, all of my species love the cichlid flake mix I get from him.