Detailed Product Description bio ballFeatures:1)For use with any external or trickle-type filter2)Special structure of the balls to guarantee maximum flow rates at high-efficiency decomposition of ammonium and nirtite through optimum oxygen supply3)Made from plastic that does not react with water4)we have different size of bio ball:32mm,42mm,48mm,26mm,36mm,46mm,56mm,76mm32mm bio-ball,quantity: ...