Question about the Chemistry of Swimming Pool "Total Alaklinity"

[u/eesemi77]

I don't understand the swimming pool maintenance concept of "Total Alaklinity"

From my High School Chemistry: If I mix Calicum Hydroxide and HydroChloric acid together in a swimming pool then I would expect any excess Hydroxide ions to combine with any available H+ ions to form water. The end result should be CaCl + H2O

I would expect the reaction to happen almost immediately, yet Pool maintenance talks about Total Alaklinity acting as a ph buffer to reduce swings in the water ph over time. To my thinking, the ph of the pool water will be determined by the residual ions either OH- or H+. there's no magical "ph Buffer" that stores this "Alaklinity" without itself changing the ph.

What don't I understand about this reaction?

Edit: Background a recent change in the Pool maintenance company has seen my chemical use more than double (before just HCL) now HCL plus "Alaklinity buffer". Result, I use almost 3 times as much acid as I used to.

Edit2: if anyone else is struggling this is the most useful site I found

https://blog.orendatech.com/total-alkalinity-role-water-chemistry

As others commented it's all about the Carbonic Acid > Bicarbonate + H+ reaction

[u/happyerr]

Total alkalinity is another way of describing buffer capacity (also high school chemistry). Here is a refresher: https://en.wikipedia.org/wiki/Buffer_solution#Buffer_capacity