Raising alkalinity in pool is beating me

Plain baking soda, the same stuff sold as alkalinity increaser for a lot more money. Roughly a pound and a half per 10,000 gallons lifts it about 10 ppm, and you're aiming for somewhere around 80 to 120. The mistake is dumping it all in at once and testing straight away. Add it in a couple of doses with the pump running, wait several hours, then retest. Don't use soda ash for this, it shoves the pH up much harder than the alkalinity.