Baking soda vs soda ash: Baking soda for alkalinity, soda ash for pH

Baking soda raises alkalinity without spiking pH, while soda ash raises both. Pool stores sell baking soda as “alkalinity increaser” at four times the grocery store price. Use 1.5 pounds per 10,000 gallons for a 10 ppm alkalinity boost. Don’t confuse them — soda ash is for pH, baking soda is for alkalinity.