Nevertheless, with any addition of chemicals (with few exceptions, for CYA, PolyQuat, etc.) you want to pour slowly over a return flow in the deep end with the pump running. For extra safety, lightly brush the side and bottom of the pool in the area where you added chemicals in order to thoroughly mix them. Chlorinating liquid or bleach is denser than water so if dumped in quickly can settle to the bottom, but the same is true for granular chlorine. Above ground pools typically do not have floor drains so have poor circulation at the bottom of the pool so some manual mixing is wise.