I have more than I know what to do with. Maybe I am doing it right but I don't know.
Mine are in a 100 gal aquarium, I have an undertank heater, and a ceramic heater on top. I alternate between eggs crates, and a plain piece of cardboard to keep them from being on top of each other as much as I can. Mine are in a huge tank as I am lazy, and Hate dubia. I keep them because they are good feeders. Anyway I keep the bugs in about 2/3 of the tank and the other 1/3 is for food plus any waste I move all the way to the far mostly open end. That was I don't have to clean them 2 x a week like crickets rater I clean them every 2 weeks.
I feed them water crystals, a dry gutload, and the same veggies as I feed my crickets. Dubia in my expierence will eat half the world if you offer it/
If you have any questions I can help with just let me know.