Quote Originally Posted by joecus View Post
I don't know if you saw the full question
Sorry;
washing soda = sodium carbonate (strong effect on pH; moderate effect on carbonate alkalinity)
baking soda = sodium bicarbonate (moderate effect on pH; strong effect on carbonate alkalinity)
borax = sodium tetraborate (strong effect on pH, no effect on carbonate alkalinity; some effect on total alkalinity)

Borax is inhibits algae; carbonate alkalinity encourages it.