The maximum dose is 7 half teaspoons per day. While taking sodium bicarbonate you should be checking your pH daily and let that guide you in how much to take. Problems with over alkalinization can occur if you take too much orally.
If you are 65 or older, the maximum dose is 3 half teaspoons/day. Elderly people metabolize bicarbonate much differently than younger people and so they do not need as much in their system at one time as it can accumulate due to natural slowing down of normal bodily functioning.
How do I get my hands on pH strips?