Tower basin would be best ...
Published by Arockia Liborious, Technical Group Lead at Nalco Water - An Ecolab Company
Tower basin would be best location as much as close to the make up water addition. If concentrated acid is used then care should be taken such that it is diluted or dosed into the center of the tower. ON/OFF or proportional control will suffice for a cooling tower. However PID control will be more accurate and optimal. Above all periodic maintenance is essential ensuring safety and reliability.