There is only a single light soda used to adjust pH value increases to more alkaline is that this month the water pH value is mainly as an acid. It requires a lot of waste caustic soda rather than other chemicals.
There is only one hydroxide is used to adjust the pH to a more alkaline water coming shows that in the most acidic pH values, the need to use chemicals other than sodium hydroxide consumption.
There is only one more caustic soda used to adjust the pH pH as more shows that this month the water coming mostly pH acid The need to use caustic soda chemical waste than another.