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Thread: My TA. Always drop down.

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    My TA. Always drop down.

    Hello my TA always drop down what can be the reason.
    last maesuring is.

    ph 7.2
    chloor 0.8 (i put in 8 gram dichloor) every day.
    0.8 is after 24 ouhr.
    TA is 030.
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

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    Mod Squad JVTrain's Avatar
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    Re: My TA. Always drop down.

    Dichlor and Trichlor are both acidic. Any time you add acid to your spa, the TA will go down. This includes muriatic acid, trichlor or dichlor. If you can switch to using just bleach, you will not be lowering your TA with bleach additions.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: My TA. Always drop down.

    Ok Thanks.

    is iT possible to tell me witch bleach jou mean and can i buy iT in the netherlands
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

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    Mod Squad JVTrain's Avatar
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    Re: My TA. Always drop down.

    I definitely do not speak Dutch or know what is available, the best I can determine from internet searching is that it may be called "dunne bleek" or "Bleekwater fles". Just be sure that it only lists "sodium hypochlorite" and "sodium hydroxide" as ingredients.

    Thought this was mildly helpful: Expatica Community | The Expat Social Network - Where is the Bleach?
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: My TA. Always drop down.

    Can i solved this problem to ad one time a week baking soda aproxematly 30 gram or 50 gram.
    or is this not a good idee for the water quality
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

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    Mod Squad JVTrain's Avatar
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    Re: My TA. Always drop down.

    That will keep your TA higher where it's supposed to be to stabilize the pH, but each time you add dichlor, you are adding both free chlorine (FC) and cyanuric acid (CYA). Eventually, your CYA will be too high and you'll need more FC to maintain sanitation. This will work for a short time, but after a while you'll need to drain and refill to eliminate the high CYA levels.

    In your volume spa, 8 grams of dichlor will raise your FC by 4.9 ppm, CYA by 4.5 ppm and lower pH by about 0.19. After 30 days if you add 8 grams every day, your CYA will be at 135 ppm. After 60 days, 270 ppm. So your spa would likely start to get cloudy, unable maintain adequate chlorine some day after 1 month of this type of daily addition. Your TA will also be dropping down because of the acidic dichlor.

    What I would do is try to find a source of plain, liquid bleach (sodium hypochlorite) if you can. When you fill the tub with new water, use dichlor for up to 5 days, then only use bleach to sanitize after each soak.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Richard320's Avatar
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    Re: My TA. Always drop down.

    Since you're only dealing with a spa and it gets periodic water changes anyway, I wouldn't worry too much about CYA buildup. If it gets too high, dump the water out and start again.

    For the short term, just raise TA with baking soda. As long as pH is good and you have enough FC to oxidize everything, enjoy.

    If you want to try bleach, Sodium Hypochlorite is commonly used as a sanitizer in dairy barns. If you can't find large quantities of strong bleach in the grocery store due to EU regulations, check out farm supply stores. The chemical formula is NaClO Generally available in 12.5% strength.
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    Re: My TA. Always drop down.

    For a spa with the Dichlor-then-bleach method, the Dichlor is only used initially for a week or so to intentionally build up the CYA level. During that time, the TA will drop some, though not a lot. If it drops too much, then yes, baking soda may be used to increase it. Note that even cumulatively adding 40 ppm FC of Dichlor to get 36 ppm CYA, the TA will only drop by 14 ppm so not by very much. Perhaps you started with 50 ppm TA and got below 40 where with rounding in the test it might look like 30. So it sounds like you have added enough Dichlor to build up the CYA (IF you've cumulatively added enough FC -- have you been keeping track?) and can switch to using bleach.
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    Re: My TA. Always drop down.

    Ok thank jou i have contact with a company Reymerink - dé producent en leverancier van cosmetische vloeistoffen, vloeistoffen voor reiniging & desinfectie en vloeistoffen voor industriële toepassing they sell chemicalien i hope i can get the bleach (bleek).
    By the way i use now thirt day (3e dag) dichloor, so i can stop and change to bleach.

    Thanks everyone for helping.
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

  10. Back To Top    #10

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    Re: My TA. Always drop down.

    Is this the right product.

    Zwembad chloor 25 kg - ongedierteman.nl
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

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    cvgnus's Avatar
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    Re: My TA. Always drop down.

    This appears to be the right product (sodium hypochlorite) according to the "more information" tab but I cannot figure out what the concentration is. The pdf mentions 10mg per liter and 3mg per liter. Sodium hypochlorite will degrade over time and more quickly if not stored a in cool and UV free place. So you may want to check the freshness of the product and perhaps look into purchasing smaller quantities since your spa is 225 gal and this is 25 kg (6.6 US gal). This product also seems quite expensive if it is similar concentrations as sold in the US.
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  12. Back To Top    #12

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    Re: My TA. Always drop down.

    I have found a company they sell it in my town and i have buy my self one.(i hope this is the right one)

    €30 for 25 ltr





    How much every day may i put in in my spa?
    I try pool calulator but for 100% shure i will check it thanks.

    Chemgeek answer in another post,( so around 8 grams of Dichlor or 50 ml of 8.25% bleach) but this is 12,5%?????.

    Factory says 20 ml a day, or i,m wrong



    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

  13. Back To Top    #13

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    Re: My TA. Always drop down.

    You should use PoolMath from the link at the top of this page, not The Pool Calculator that is older, no longer supported, and has some errors.

    If you switch "Units" in the upper-right-hand corner of PoolMath to "Metric", then put in 850 liters (225 gallons is 852 liters so closer to 850 than 900), and put in "12.5" before the "of ____ weight/trade % bleach, then put in a Now for your current FC level and a Target of what you want, so let's say you put in 0 for Now and 10 for Target as an example, then this gives 68 ml of 12.5 trade % bleach. In other words, it's 6.8 ml (about 7 ml) per 1 ppm FC for your spa.

    However, if you are using the spa then the amount you dose isn't calculated based on an FC value but rather on how many people are in the spa for how long for a soak. Remember that I wrote that every person-hour of soaking in a hot (40C) spa with no ozonator needed roughly 3-1/2 teaspoons (16 grams or 16 ml) of Dichlor or 3-1/2 fluid ounces (104 ml) of 8.25% bleach or 7 teaspoons (45 grams or 35 ml) of non-chlorine shock (43% MPS) to oxidize bather waste. For 12.5% bleach that you have this would be around 2-1/2 teaspoons (72 ml) of 12.5% bleach.

    HOWEVER, you have an ozonator so would likely only need to add around half these amounts. So if you are still using Dichlor to build up CYA, try using 8 grams (should be around 8 ml) of Dichlor. If you have already added 33-44 ppm FC cumulatively of Dichlor (51 to 68 grams) to build up CYA and have now switched over to using bleach, then try using 36 ml of 12.5% bleach. Just remember that the real rule is to add whatever amount is necessary so that you don't let the chlorine get to zero before your next soak and preferably start your next soak with around 1-2 ppm FC though if it's somewhat more that's OK (most people prefer to soak starting with a low FC level so that they don't notice the chlorine, but that's up to you). You will have to learn how much needs to be added after each soak to last through to the next soak since every ozonator is different and I have no way of knowing how powerful yours is or how long it is running.
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    Re: My TA. Always drop down.

    Thanks for helping chemgeek.
    My spa is 225 gallon (ca 900 ltr)
    Factory is Caldera
    Above ground
    6 months old now.

  15. Back To Top    #15

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    Re: My TA. Always drop down.

    Just to jump in.
    I use the same 12,5% and with a perastaltic pump i add 50ml on daily base to establish a continue FC level 3-6. When using the spa i have to add 40ml per person/per hour to keep FC level.
    Boric acid (boorzuur) is available on internet also in the Netherlands. Used vd lange drogisterij but it seems they stopped with boric acid so a have to find a new source.
    Muriatic Acid (zoutzuur) is avalable in the professional building shop's, so no diy shop like gamma. The professional shop's sell MA in a 30% solution (tahe good care when handling and store outside in a cool place out of the sun)
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