Pool and spa water quality control system and method

A water quality management system for a water installation containing water, the system comprising:

• a water quality measurement module adapted to monitor the water quality of the water in the water installation and to send water quality information to a controller;
• and
• a chemical dispensing module adapted to dispense a powdered chemical and a liquid reagent directly into the water installation through one or more openings in an exterior surface of the chemical dispensing module in response to signals from the controller based on a water quality measurement by the water quality measurement module,
• the chemical dispensing module comprising:
• a first reservoir adapted to contain the powdered chemical,
• a first dispenser adapted to dispense powdered chemical from the first reservoir through the one or more openings into the water installation,
• a second reservoir adapted to contain the liquid reagent, and
• a second dispenser comprising a holding chamber in fluid communication with the second reservoir and having a volume smaller than a volume of the liquid reagent reservoir, the second dispenser adapted to dispense liquid reagent from the holding chamber through the one or more openings into the water installation.