... any external or trickle-type filter2)Special structure of the balls to guarantee maximum flow rates at high-efficiency decomposition of ... not react with water4)we have different size of bio ball:32mm,42mm,48mm,26mm,36mm,46mm,56mm,76mm32mm bio ... ballquantity:750pcs/bag26mm bio-ball(sponge inside)quantity:4000pcs/bag36mm bio-ball(sponge inside)quantity:1500pcs/bag46mm bio-ball(sponge inside)quantity: ...