Hard to tell what the red things are without a picture, so I won't venture to assume that its part of the CGD until I see what you're talking about. But hey, if you want to wean your gecko off crickets, go cold turkey and just feed the cgd for a straight month or more. He is holding out for the crickets, which is why he's not appearing to eat much of the CGD. Once you offer only CGD, he won't have a choice and will have to eat the CGD. A healthy gecko will not starve itself, he may lose a little weight from being stubborn, but he won't starve. They can go a long time without eating, so you have to be more stubborn than the gecko.
Help! Crested Geckos! 0.1.Leachie, 2.1.1 Gargs, 1.0 Chahoua, 2.1. Blue Tongue Skinks, 1.1. White Lined Geckos, 1.3. African Fat Tails, 2.2.0 Tokay Geckos, 1.0. Giant Day Gecko, 2 tarantulas