Total Alkalinity Is The Referee For The Pool Water!
Too High It Forms Scale, Clouds Water, Clogs Filters, Stains Surface.*ALSO, REMEMBER WHEN I SAID "If your pH is too high you will reduce the effectiveness of your purchased chlorine down to 2%.....Blah blah blah." It's happening all day long and can lock into high pH that's hard to lower! See The pH Blog Here
Too Low: Etches and Eats Everything, Corrosive therefore staining easily and the pH will be erratic all day long bouncing up and down. Remember when I said "Rapid chlorine burn out, water corrosive to all it touches. Reduces life of filters system, o'rings, pool cleaner plastics, pool fittings and all metal parts...Blah blah blah." See pH Blog here
Too High: High chlorine absorption, calcification off all plastics and metals as well as pool surface if porter cement based. Also, rubber swim toys wear as they become dried. Water becomes too soft and burns as well as extreme drying of skin and hair. The calcification alone can lead to the total resurfacing of the pool surface and at the very least an acid bath to remove the build up and a possible bead blast job on the tile to remove the tile line calcification. By this time your filter media has also dried and worn from the high pH and you had to replace them sooner than later and the pool has been hard to keep algae out of as the chlorine is working at maybe 3 to 8% which leads to depending on costly algaecide treatments to rapidly clear the pool. Overall, costly all the way around.
Bonus Below. This is one of the best county pool chemistry presentations I have seen. There is a pdf handbook that matches the section in the audio training. If you really want to get a little deeper understanding of taking care of your 25 to 60K dollar investment you may want to spend a moment checking this ph section out.