Thank you all.

Maybe this will help. The ph from from the municipal water supply is 7.8.

My pool is 9,000 gals, try to keep ph at 7.4 it rises to 7.6 by nightfall. 7.4 is ideal because of iron issues from Hawaii's red dirt - ferric oxide - primarily in the airborne dust as tradewinds blow normally at 12-18 mph.

Alk maintained at 100 to 110 (CYA adjusted), calcium at 260, tds at 700, 3 ppm chlorine by nightfall adjusted back to 6 at nightime, CYA at 35 (may raise this to 40, then 45, and a max of 50 to try and keep chlorine demand down).

Hope this helps in any calculations or ideas on how to lower chemical costs.