To answer your "how much for 14,000 gallon?" question:

In a 14,000 gallon pool, every pound of Baking Soda or Sodium Bicarbonate or Alkalinity Up will raise the Total Alkalinity (TA) of your pool by 5.5 ppm.

Every pound of Washing Soda or Sodium Carbonate or most pH Up products will raise the pH of your pool by 0.44 and your TA by 8.7 ppm if you initially start with a pH of 7.5, TA of 80 and a CYA of 30. The effect on pH is very dependent on your starting pH and on your TA and CYA levels.

Every pound of 20 Mule Team Borax will raise the pH of your pool by 0.20 and your TA by 2.4 ppm if you initially start with a pH of 7.5, TA of 80 and a CYA of 30. The effect on pH is very dependent on your starting pH and on your TA and CYA levels.

Generally speaking, you add about twice as much (by weight of) 20 Mule Team Borax to have the same effect as Washing Soda / Sodium Carbonate / pH Up.

Richard