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Thread: Help "shocking" a spa

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    Help "shocking" a spa

    Split by moderator from HERE. jblizzle

    When "shocking" your hot tub by bringing FC up to 12....

    do you need to leave the cover off for a while? if so, how long?
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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    Re: How do I use Chlorine in my Spa (or pool)?

    There isn't a need for a regular shocking on a schedule, but for shocking (meaning just raising the oxidizer level substantially) to handle bather waste after a soak you usually want to keep the cover off at least for a half hour though an hour would be better. However, when it's very cold outside during the winter, people usually don't want to keep the cover off for very long. Most of the volatile oxidation products are produced in the minutes after you add oxidizer after your soak.

    Also, you should remove the cover for about 10 minutes before your soak to let any buildup of volatiles air out. If you don't have a breeze, you can briefly run the jets. This should make your hot tub experience more pleasant with minimal smell from the sanitizer or its disinfection by-products.
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    You can switch from chlorine to bromine or vice versa upon a fresh drain/refill. You can even switch from chlorine to bromine by simply starting to use bromine tabs and adding sodium bromide to create a bromide bank.

    I am going to be out of town for 8 days in September...

    I'm currently using chlorine in my hot tub, testing and adding chlorine on a daily basis. No one I know has the ability to hot tub sit for me over those 8 days, so is using bromine a viable option? How much bromine would I need to add, and would it last for 8 days?
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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    Re: How do I use Chlorine in my Spa (or pool)?

    You can use bromine tabs in a floating feeder and they can easily last a week (some people put a bunch in two feeders on a low setting to last for 2 weeks). However, when you get back you will now have a bromine spa until your next refill. If you don't add any sodium bromide, then perhaps the bromine will eventually dissipate. Anyway, this shouldn't matter, but you may notice a different smell with bromine than with chlorine. As for your testing and dosing when you get back, there is no change. You can use your existing chlorine test kit -- just note that the Total Bromine or combined bromines will measure as Free Chlorine (FC) in the test (which is OK since bromamine is still a disinfectant).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    You can use bromine tabs in a floating feeder and they can easily last a week (some people put a bunch in two feeders on a low setting to last for 2 weeks). However, when you get back you will now have a bromine spa until your next refill. If you don't add any sodium bromide, then perhaps the bromine will eventually dissipate. Anyway, this shouldn't matter, but you may notice a different smell with bromine than with chlorine. As for your testing and dosing when you get back, there is no change. You can use your existing chlorine test kit -- just note that the Total Bromine or combined bromines will measure as Free Chlorine (FC) in the test (which is OK since bromamine is still a disinfectant).

    So, I can simply add bromine tablets to a feeder? No need for the sodium bromide bank?


    Should I have my FC at a certain level when I add the bromine tablets?
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    Re: How do I use Chlorine in my Spa (or pool)?

    If you use BCDMH (bromo-chloro) tabs, then it would be better to have a bromide bank for the chlorine to convert the bromide to bromine. Otherwise the chlorine will outgas quickly since there is no CYA in the water. If you use DBDMH (bromine-only) tabs, then you don't need a bromide bank unless you were going to separately shock with chlorine.
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    If you use BCDMH (bromo-chloro) tabs, then it would be better to have a bromide bank for the chlorine to convert the bromide to bromine. Otherwise the chlorine will outgas quickly since there is no CYA in the water. If you use DBDMH (bromine-only) tabs, then you don't need a bromide bank unless you were going to separately shock with chlorine.
    I actually do have CYA in the water....I used dichlor initially to get CYA around 30, then I switched to bleach.

    Any idea which type of tablet these are?: Diamond Spa Bromine Tablets
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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    Re: How do I use Chlorine in my Spa (or pool)?

    Since you have CYA in the water already, don't worry about the type of bromine tabs. If they are BCDMH, then the chlorine in them won't outgas that fast because of the CYA so not having the bromide bank is not a problem. Your spa will have a mix of chlorine and bromine, eventually getting more bromine as the bromide builds up from spent bromine.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    Since you have CYA in the water already, don't worry about the type of bromine tabs. If they are BCDMH, then the chlorine in them won't outgas that fast because of the CYA so not having the bromide bank is not a problem. Your spa will have a mix of chlorine and bromine, eventually getting more bromine as the bromide builds up from spent bromine.

    Ok....so....I'm leaving today around 11 am.

    How many bromine tabs should I put in a floater if I'm going to be gone until Saturday 9/8?


    What should I adjust my FC to?
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    Re: How do I use Chlorine in my Spa (or pool)?

    Raise it to 10 ppm FC and put in one tablet in the feeder. That should be more than enough for 8 days.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    Raise it to 10 ppm FC and put in one tablet in the feeder. That should be more than enough for 8 days.
    And when you say "feeder", you mean floater, like this?:
    http://www.hottubworks.com/part-MP1973E ... tgodcBoAwA

    ??
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    Re: How do I use Chlorine in my Spa (or pool)?

    Yes.
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    Raise it to 10 ppm FC and put in one tablet in the feeder. That should be more than enough for 8 days.

    Ok....just got back from vacation.

    The floater still has a small amount of the 1 tablet I put into it when I left....probably about 25% of the tablet.

    I tested the FC / Bromine using the OTO test, and it shows around 1....

    question is: I'm not sure if I'm measuring bromine or chlorine....or both?

    Now that I'm back and able to perform maintenance, what should I be doing? Just keep using the bromine tab in the floater, and adding chlorine after using the hot tub?
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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    Re: How do I use Chlorine in my Spa (or pool)?

    Yes, just keep the tab in and add an oxidizer (such as bleach) as needed. When the bromine tab is used up, just use chlorine as you did before.

    The test does not distinguish between bromine and chlorine. 1 ppm FC is equivalent to 2.25 ppm total bromine. So it sounds like this worked out though perhaps the feeder could have been open more or perhaps needed 2 tabs for a slightly higher feed so that you'd have 2 ppm on average, but 1 ppm is a lot better than zero.
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    Re: How do I use Chlorine in my Spa (or pool)?

    Quote Originally Posted by chem geek
    Yes, just keep the tab in and add an oxidizer (such as bleach) as needed. When the bromine tab is used up, just use chlorine as you did before.

    The test does not distinguish between bromine and chlorine. 1 ppm FC is equivalent to 2.25 ppm total bromine. So it sounds like this worked out though perhaps the feeder could have been open more or perhaps needed 2 tabs for a slightly higher feed so that you'd have 2 ppm on average, but 1 ppm is a lot better than zero.

    The tab is pretty much used up, so I went ahead and added 2 tablespoons of dichlor, as I haven't added any in about 6 weeks.

    I'm keeping the hot tub at it's lowest temperature, as we don't plan on using it for another week or so.

    That being the case, I'd rather not be adding chlorine every other day. So....I should just throw another bromo/chloro tab in the feeder?

    Is there a particular pH I should be shooting for?
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    Re: How do I use Chlorine in my Spa (or pool)?

    Yes, you can put in another tablet and if you aren't using the tub it should keep it sanitary and it good shape without you having to add any chlorine in between. That's the primary advantage of using bromine -- that in between uses the tabs keep dosing out sanitizer. The pH should just be kept under 8.0. With the cooler water and no use, having it at 7.8 should be stable though if it's stable at 7.5 that's fine too.

    Just keep in mind that by using more bromine you are building up a bromide bank. That means that even when you stop using tabs in a couple of weeks, that you will essentially have a bromine tub. Any chlorine you add will oxidize bromide to bromine. That's fine, of course, but you may notice a different sort of smell especially if you start a soak with higher sanitizer levels (bromamines smell different than chloramines and some people don't like it). Your dosing for bather load should be similar to what you did before when it was a chlorine spa. You can return to a chlorine spa with your next water change.
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    Re: How do I use Chlorine in my Spa (or pool)?

    So I should be maintaining around 2 - 4 ppm bromine while the tub is not being used?

    And when I do soak, afterwards I should add enough chlorine to get to 6 ppm?
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

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    Re: How do I use Chlorine in my Spa (or pool)?

    Yes, see if you can maintain 2-4 ppm bromine in between use. As for after a soak, you should use the amount of oxidizer needed to oxidize the bather waste - it's not a fixed bromine level since it depends how long you soak and the size of your tub and is the same amount of oxidizer as when you use chlorine. If there is no ozonator, then every person-hour of soaking in a hot (104F) spa needs around 3-1/2 teaspoons of Dichlor, 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS). If you have an ozonator, then you might need only half as much. Basically, just add whatever amount you need such that you get back down to the 2-4 ppm bromine before your next soak (or after 24 hours).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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