Hello, I mixed seachem matrix stones with bio balls in my sump. Recently I put the stones in a mesh bag to avoid a mess of stones when cleaning the sump. However, the bag turned out to be slightly smaller than the area where the stones were. So new there is a one inch gap in all for sides of that area, leaving some water to flow through without touching the bag. But, and I put emphasis on the but, I placed the bio balls on top of that bag so they cover the gaps and the water flow touches all. My tank is pretty well acclimated but my question is if the gap would cause any issues flowing through good bacteria. I'm sure the bio balls are doing their job in that sense too but I'm not too crazy about those round plastic balls. Your opinions count.