I ordered two starter cultures from Joshs Frogs and after moving them into a larger container and a few small pieces of white rice, ended up with tons of them in no time.

Once the culture is going strong you should never run out since they just keep reproducing.

My biggest issues with springtails was trying to get them into the tank and not flood the tank. Today I figured that out. I added some water and tilted the container to let them float to the surface, then took the container to the viv and tilted it to get the water near the edge. The springtails started jumping out on their own and when I blew across the top of the charcoal it looked like a snow globe of springtails in the air.