Raising pH and Alkalinity

[CarlD]

While T/A and pH are connected, the cause and effect isn't that obvious. A lower T/A won't cause your pH to drop. My pH is good and my last T/A reading was ...40! T/A's main function is to keep pH from fluctuating. If it's not fluctuating, it's not a problem. Some of our SWCG experts tell us that the for an SWCG, the T/A is BEST kept low--between 60 and 80.

When you raise your pH with Borax or Washing Soda, you'll see your T/A increase as well.

No need to make it complicated.

Carl

[chem geek]

The simplest way to think about it is that TA does TWO things: 1) it buffers pH which means a higher TA tends to resist changes in pH from EXTERNAL SOURCES such as acid addition or bleach addition and 2) TA is a SOURCE of rising pH in its own right due to increased carbon dioxide outgassing (i.e. pools are over-carbonated and the TA tells you by how much). These two factors compete with each other with the second being dominant at higher TA. So this means that a higher TA level will cause the pH to rise in a pool, assuming you aren't adding acid in any way, including use of Trichlor pucks or Dichlor powder. Every pool has a "sweet spot" TA level that is low enough to not notice a pH rise. This TA level varies by pool because the rate of pH rise is accelerated by increased aeration of the water so pools with waterfalls, fountains, spill-overs, vanishing edges, etc. tend to need a lower TA level to get reasonable pH stability. The same is true for saltwater chlorine generator pools, partly due to hydrogen gas bubbles increasing aeration.