I like using the 3 drawer Rubbermaid containers. That way you can keep you beetles separated from your worms in the same container. Also, I use oats as the substrate. Not the instant ones either
I just use a 16 qt tub for the mealworms, a 6 qt for the beetles, and a random deli container for the cocoons. I also use oats, but wheat bran is cheap and popular also
How many meal worms can you keep in each 16 qt tub (approximately). I was thinking of making a mini rack system 4-5 shelves tall of 28 qt 3 wide so its easy to just move the meal worms from bin to bin. Can just plain oatmeal without anything added be used? Also how long after moving the beetles in do you move them out.
I have over 4000 mealworms in my tub, and if it starts getting crowded, I just make the substrate deeper And this is a link to how I successfully breed mealworms, and it has detailed instructions for every stage of mealworms: http://geckoforums.net/f128-feeding-feeders/97779.htm I hope you find it useful