Effectiveness of Chlorine in high pH water at H2S and Bacteria Removal

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Beets

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Hi Folks,

I'm contemplating switching my treatment system back to sodium hypochlorite from hydrogen peroxide. I'm looking for some information.

I have two problems. I have some slime producing bacteria (see this post) and I have H2S. I used to struggle when I used chlorine with occasional upsets, but that may have been my own doing as I would buy 9 to 12 months of sodium hypochlorite at a time. I know chlorine has a shelf life. How long is the maximum that I should store chlorine?

The second question is what is the impact of pH on chlorines effectiveness? My pH is 8.6 to 8.7 from two water tests.

The internet is full of charts like the following:

1647430536648.png

Is it the HOCl that kills bacteria or OCl? Same question for H2S. Or neither?

When I use a chlorine test kit (I use the ones for a pool where you add drops and compare shades of yellow), is it measuring the HOCl or the OCL? Or neither?

People tell me to target a residual chlorine of 0.5 to 1 ppm before going into my centaur carbon filter. I've never found that to be effective. I've always felt I have to treat at much higher residuals. Could it be the pH that is driving this, my imagination, or lack of contact time? My best test for whether the system is working is my nose and early morning showers where the contact time is >8 hours. Thus, I'm skeptical contact time is the issue, but I thought I would ask. I have a 80 gallon contact tank.

Thank you
 

Reach4

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The bleach I buy is stabilized by adding some sodium hydroxide. Regarding killing power, the lower the pH, the better. But you want to not get into the Cl generating pH for safety reasons. But it sure kills.

I am going say that the HOCl is the much better killer vs OCl. I suspect that OCl is still a killer but needs higher concentrations.

In the chlorine test area, I wonder about some of that myself. I usually use the free chlorine test as a good indicator of killing power, but I am confident that it responds to the HOCl form. I try to stay out of the actual Cl part of the graph. Is total chlorine including products from the bleach being spent, or is it just including the less active but not-spent stuff like chloramine?

I plan to try to treat my 9.3-year old Centaur Carbon soon. My CC filter is my front end filter. My plan is to use Iron Out solution recirculated with a utility pump. I am hoping for orange solution, which I will pump out. I bought a new white trash can to put the pump into. White for better observation.

I may repeat the IO solution, depending on what I see. Then I expect to follow with a bleach solution, possibly with vinegar.

I am open to suggestions.

In buying bleach, I would stay away from the ones with polyacrylate. I cannot be sure that would not be better to have the polyacrylate for my media treatment, but it doesn't feel quite right.
 
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Beets

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Thank you, is there an upper pH limit where chlorine is not recommended? Do folks ever reduce the pH before they treat with sodium hypochlorite in order to keep bacteria under control?
 

Gsmith22

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see your other tread where I talked about what you are doing with relationship to pool sanitation. Pools are supposed to be kept at pH between 7.2 and 7.6 for effective chlorine use.
 
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