Chlorine problems

  • Last Post 12 November 2020
Jim1952 posted this 11 June 2020

I have a fiberglass pool, 9000 gallons. Water balancing has always been tricky. Chlorine will read 1 or zero most of the time, unless I've just shocked the pool. Last week I went through 9 three inch tabs of chlorine  in my Heyward Inline Cholorinator, and after shocking I still have a low chlorine reading of only a .5. (I have even added a gallon of stabilizer as directed by Leslie's new water analysis system, but to no avail). 

I have had a high alaklinity reading of 18 ppm, so dry acid has been added. This morning the reading for alkalinity is now at 4.6 and the ph is at 6.5. I have just added 2 pounds of soda ash.


All of this to information to ask, "Could the high alkalinity level be neuteralizing the chlorine?"

Anyone have any insight? 

rayashcraft posted this 12 November 2020


I've a Hayward CL200. I had Chlorine 5, Alkalinity 90 and PH 7.5 yesterday in the evening. I use Chlorine neutralizers: Sodium Sulfite and Sodium Thiosulfate. As a rule, 60 grams reduces the chlorine level in my pool by 1ppm.

Chemistry case study: Sodium Sulfite | Sodium Thiosulfate