I will be filling my pool again soon, so I am getting a fresh start on my water. With the advice of TFP I have been having progressively better results putting less in it each year. Visitors have commented on my pool water being very nice.
My tap water has a TA of 30. Best I can tell my tap water has a pH of 9.6. To measure this I mixed 2 parts of pH 7.2 distilled water with one part of my tap water. This tests as pH 8.
Assuming pH's average each other I computed my tap water pH as follows.
( pH + 7.2 + 7.2 )/3 = 8
pH + 14.4 + = 8 * 3
pH = 24 - 14.4 = 9.6
Adding the 72 ounces of baking soda to get my TA to 100 will probably add another 0.15 to the pH.
Adding the 23 ounces of CYA will probably drop the pH 0.75.
Last year I added muriatic acid to bring the pH down right away, but I wonder if I should bother at first. My water will drift more acidic over time.
What I am thinking of doing is adding the baking soda and CYA, maintain a fairly high chlorine level of about 8, but not worry about the high pH until the water is warm enough to swim in. With only 4.4k gallons of cold water the bleach bill will be very low.
When the temperature get to swimming temperature, about 67F, adjust the pH to 7.4.
Is this a good idea, or should I adjust the pH right away with the muriatic acid? One good point of dropping the pH now is I would be adding borax sooner and getting some borate in there.