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Thread: pH of bleach

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    pH of bleach

    This is one aspect of the BBB method that I am unclear about. I started using the BBB method along with Trichlor in chlorinator about two years ago. One thing I noticed right away was that the bleach seemed to increase my pH if I used it exclusively. This is why I started using it in conjunction with Trichlor. I figured if I balanced the amounts of each I was using I could actually control the pH without the need to add borax or muriatic acid. I have to say that I have not had great luck with the BBB method thus far. I have recently come across this website and the Pool School and have learned a tremendous amount the info I was missing to more completely balance my pool. I feel confident that I will have great success this summer. The most important thing I learned was how to eliminate the constant algae problem I have battled for two years. So, if someone could explain the pH of bleach thing I would greatly appreciate it. If I Google the pH of bleach, I get many results of about 12.5. You would think that this would warrant having to control that when using it in your pool as you primary chlorine source, but I have not seen this addressed on this website or forum yet. Please advise. Thanks.
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    Re: pH of bleach

    Welcome to TFP!

    There are some chemistry gurus on here who can explain this concept with a little more depth than I, but I can offer that trichlor tablets are acidic and will keep pH rise in check for a little longer than bleach will. This pH stability comes with a price though, this being the extra cost of the tablets and the extra components that trichlor adds (CYA and in some brands, copper). Bleach is salt, water, chlorine, and lye.

    Not all bleaches are created the same either. Some bleaches have more lye than other bleaches. There is a thread here somewhere that discusses this topic and I cannot find it, but basically, some cheaper brands of bleach tend to have more of a variance in pH from lot to lot than does, say, Clorox. All bleach tends to the alkaline side of things though because of the lye.

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    Mod Squad JohnT's Avatar
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    Re: pH of bleach

    Bleach only temporarily raises the pH of the water, and even if the change was permanent, the effect of one gallon of a solution with a pH of 12 will have almost no effect on thousands of gallons of a water with a pH around 7.
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    dmanb2b's Avatar
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    Re: pH of bleach

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    Re: pH of bleach

    When you add bleach the pH goes up, and then as the chlorine gets used up the PH goes back down again. The net effect is very close to PH neutral. Trichlor, on the other hand, lowers the PH slightly when added, and then the PH goes down more as the chlorine gets used up.

    Most trichlor users are constantly adding soda ash to compensate for the effects of adding trichlor. Most bleach users don't need to do very much, because the PH stays more or less balanced.

    There are other things that can affect the PH. For example high TA levels will tend to raise the PH over time, sometimes quite quickly if there is enough aeration. In some cases this effect can be balanced out by the PH lowering effect of trichlor.
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    Re: pH of bleach

    The reference to the Aldi bleach post was very informative, especially because that is the current bleach I am using since I found it to be the cheapest in my area, $1.09 per 96oz bottle. I am currently shocking with bleach to 16 FC as I kill off algae while opening my pool. The Leslie's FAS-DPD test kit I bought today read pH between 7 and 7.2. Before that I was using hTh test strips from Walmart which were reading pH between 7.5 and 7.8. I have a feeling the high chlorine level is affecting the test strip reading. I am not sure that the test kit reading is accurate either since I had the water tested at Leslie's on Saturday and Sunday and they were reading 7.5. I do think the pH is on it's way down from when I first put the initial shock amount in (20 bottles) on Sunday around 3:00PM.

    Current readings: FC 17, pH 7.1, CYA 45, TA 80, CH 80
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    Re: pH of bleach

    Don't test pH when FC is above 10 because you can get a false high read.
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