Re: A new way I've been culturing springtails.
With hydroballs you run into the same problem as charcoal in that it isn't as easy to get the springtails out of your cultures. This method makes that much easier than any other culturing methods I've tried and you can also make lots of cultures at the same time. As far as putting clay on hydroballs to culture this won't make getting them out of the cultures any easier and would also eliminate the ability to water feed. I use 8 oz deli cups with about an inch of clay in the bottom so it's not using a ton of clay anyway.
As far as feeding springtails I have never used anything other than brewers yeast and have always had good results. The couple times I've put strawberries or mushrooms in cultures I end up with grain mites.
Personally I feel that commercial food for springtails and fruit flies are unnecessary and a waste of money. The videos you see for advertisements of said products showing booming cultures can be accomplished by just adding a large number of flies/springs to the initial culture and those cultures will probably ultimately crash. Change my mind.