If you want to hatch your own BBS, you can use a paper coffee filter to strain the water from the brine. Turn the paper filter inside out over the tank and dip the filter in the tank. The BBS will come off in the water and you can dispose of the filter. The filters are very inexpensive, I have a stack of the large style that are shaped like a bowl. I place the filter over a jar with a small depression in the center so the water falls in the jar and the BBS are left on the filter. Easy to do.
Bryan