How much does liquid 6% Chlorine change PH

[smallpooldad]

How much does liquid 6% Chlorine change PH. For example to adjust a 10,000 gal pool Ben's calculator states 2 quarts for a 3 ppm move. If the the ph is 7.4 how much will it increase.

Looking forward to you replies.

Thank you

[mas985]

Bleach has a PH of about 12 but you are only adding 1 gallon to 10000 so you would not expect much of a change. If you are so inclinded, you can use this formula:

-log10(10^(-7.4)+(10^(-12))/10000) = 7.3999999989

[mwsmith2]

Hm. I would expect the pH to go up, not down. You sure that formula is correct?

Michael

[aylad]

I don't think you're going to see an appreciable difference--most people don't, if your Alk is where it needs to be.

Janet

[smallpooldad]

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.

[mas985]

Hm. I would expect the pH to go up, not down. You sure that formula is correct?

Michael

Sorry, I made an approximation. The proper solution is:

-log10(10^(-7.4)*10000/10001+10^(-12)*1/10001) = 7.4000434261859642546351588394264

And this equation is really only good for solutions without buffers so it is not that accurate for a swimming pool but I do believe it is a worst case.

[mwsmith2]

Cool that makes sense now. Bottom line is that it's an tiny tiny change.

Michael

[smallpooldad]

Thank you for this final answer.

Now I know that life will be a never-ending fight between iron and ph.

Does anyone know where I can get a tanker of muriatic cheap? And I thought gas was expensive.

[hoffmans]

smallpooldad-
Hello, I am such a newbie here I am embarrassed to write. But I have been reading Ben's Site and Forums from top to bottom for the past year. And when I saw your post I thought you might be interested in the section Ben has titled "Benefits of High pH Swimming Pools". You can find in on the main home page right under the section about "Avoiding summer ear infections".
Well there. There is my first post. I have been reading all of you verteran's posts, I feel like I have know you for years.
Enjoy your pool!
-hoffmans