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Thread: How to get chlorine levels back down?

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    How to get chlorine levels back down?

    LOL I just posted the other week about too low chlorine levels. Chlorine levels were good. Today I shocked the spa. This evening the chlorine levels are too high. Just now I took the cover off and am running the jets, hopefully some of the chlorine will evaporate?

    FCl is 10
    Total Cl is a way darker green then the highest color on the test strip.

    Thanks for any help! My wife is cold and wants to go for a dip

    Oh I should mention that I was planning on shocking the spa weekly, but I think I shouldn't now. It's just the two of us and a week later the chlorine levels were good. I should probably only shock it when the free chlorine level is low right? By shocking it now I probably put way too much chlorine in the water.
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    How much CYA do you have in there? If it's around 30, it's fine to get in.
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    Re: How to get chlorine levels back down?

    If you decide you need to lower the chlorine level, an easy way to do that is to use 3% hydrogen peroxide. 24 ml of 3% hydrogen peroxide in 1500 liters will lower the FC by 1 ppm.
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by pabeader View Post
    How much CYA do you have in there? If it's around 30, it's fine to get in.
    No reading for CYA on the test strip What's the worst that can happen if we go in tonight?

    - - - Updated - - -

    Quote Originally Posted by chem geek View Post
    If you decide you need to lower the chlorine level, an easy way to do that is to use 3% hydrogen peroxide. 24 ml of 3% hydrogen peroxide in 1500 liters will lower the FC by 1 ppm.
    Don't have any, but good to know!
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    If you haven't added any CYA/stabilizer to the tub then there isn't any in there. Unless you chlorinate with dichlor or trichlor. Both of those add CYA. You really should toss the strips and get a good Taylor drop based test kit.

    Here is how I have maintained my tub for two years and it is great. How do I use Chlorine in my Spa (or pool)?
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by pooldv View Post
    If you haven't added any CYA/stabilizer to the tub then there isn't any in there. Unless you chlorinate with dichlor or trichlor. Both of those add CYA. You really should toss the strips and get a good Taylor drop based test kit.

    Here is how I have maintained my tub for two years and it is great. How do I use Chlorine in my Spa (or pool)?
    Just checked the bottle and the they are stabilized tabs using trichlor. Your article talks about dichlor, what's the difference?
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    Quote Originally Posted by davesurfer View Post
    Just checked the bottle and the they are stabilized tabs using trichlor. Your article talks about dichlor, what's the difference?
    For every 10ppm of FC added with Trichlor you will also add 6ppm of CYA. For every 10ppm of FC added with Dichlor you will also add 9ppm of CYA.

    If you have been regularly using Trichlor there is some CYA in the water. It is not showing up on the guess strips because they are not accurate, and/or the CYA level is very low.

    What did you use to shock the spa? How long have you been using Trichlor?

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    Mod Squad pooldv's Avatar
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    Re: How to get chlorine levels back down?

    Given that you have CYA in the tub getting in it with 10ppm of FC will be fine.

    More on chlorine products here, Pool School - How to Chlorinate Your Pool

    More on pool chemicals here, Pool School - Recommended Pool Chemicals
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by domct203 View Post
    For every 10ppm of FC added with Trichlor you will also add 6ppm of CYA. For every 10ppm of FC added with Dichlor you will also add 9ppm of CYA.

    If you have been regularly using Trichlor there is some CYA in the water. It is not showing up on the guess strips because they are not accurate, and/or the CYA level is very low.

    What did you use to shock the spa? How long have you been using Trichlor?

    Dom
    I've used the ZAP pouch twice:

    WP_20151016_12_39_21_Pro.jpg

    I've been using the trichlor tabs for a bit over a week now since I filled the tub. We just bought the house in January, and when we had bought it there was a pool maintenance guy coming over and doing the maintenance (previous owner paid for). They were using the trichlor. tabs. Then we had drained the tub as we weren't able to use it till now anyways.

    Oh btw, the readings are about 4-5 FCl and 10 Total Cl. So that's come back down.
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    The IPG ZAP Oxydizer is probably MPS with some clarifier so that doesn't have CYA in it and is not a disinfectant (unless used at hot spa temperatures with silver ions) and it will lower pH and TA over time.
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by chem geek View Post
    The IPG ZAP Oxydizer is probably MPS with some clarifier so that doesn't have CYA in it and is not a disinfectant (unless used at hot spa temperatures with silver ions) and it will lower pH and TA over time.

    What's MPS? So I wonder what "eliminator" means. Is this just used for someone who wants a quick fix for cloudy water? My local store said that it was the same as shocking.

    So I found another bottle of this stuff "Boom". I'm guessing this is the stuff I use for shocking?
    WP_20151022_22_12_43_Pro.jpg
    WP_20151022_22_13_52_Pro.jpg

    I'm also assuming step 4 in the directions about "superchlorinating" is what I would do to shock the spa when FCl get low? Thanks!
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    MPS is non-chlorine shock. It is an oxidizer but not a disinfectant.

    Boom looks like Dichlor. Note that they actually say that it will increase stabilizer (cyanuric acid) levels. In fact, for every 10 ppm Free Chlorine (FC) added by Dichlor it also increases Cyanuric Acid (CYA) by 9 ppm. You would use this after each soak though you could use some non-chlorine shock (MPS) if you want or you can use the Dichlor-then-bleach method described in this sticky.
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by chem geek View Post
    MPS is non-chlorine shock. It is an oxidizer but not a disinfectant.

    Boom looks like Dichlor. Note that they actually say that it will increase stabilizer (cyanuric acid) levels. In fact, for every 10 ppm Free Chlorine (FC) added by Dichlor it also increases Cyanuric Acid (CYA) by 9 ppm. You would use this after each soak though you could use some non-chlorine shock (MPS) if you want or you can use the Dichlor-then-bleach method described in this sticky.
    Oh ok, the ZAP was what jacked up the FCl levels to maximum though, is that playing tricks on the test strips?

    So I wasn't wanting to have to add something every day or after every soak. Right now I have the trichlor tabs dispenser that floats in there all the time. I was just looking to use the floater and then do a shock only when FCl levels are getting lower.
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    Yes, the MPS can show up as either FC or as CC depending on the type of chlorine test. For most chlorine tests it shows up as CC or with test strips that would be in TC (Total Chlorine).

    So if you are soaking regularly every day or two and not for very long then you can have the pucks in a floater handle your bather load. However, this approach won't work if you soak infrequently since the chlorine demand in between soaks is a lot lower than that from a soak. Also, most people don't like soaking in higher chlorine levels and that would be needed if you have a higher bather load. So it's normal to add chlorine after a soak and leave the tabs in a floating feeder (either for chlorine or for bromine) to handle the background dosing in between soaks. So you could still use a Dichlor-then-bleach method augmented with the Trichlor puck in the feeder for background dosing.

    Just remember that Trichlor is not normally used in spas so you need to use a special feeder that slowly doses since Trichlor normally dissolves too quickly in hot water. It is also quite acidic and will lower TA over time so you'll need to add baking soda to maintain the TA level.
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    Re: How to get chlorine levels back down?

    Quote Originally Posted by chem geek View Post
    Yes, the MPS can show up as either FC or as CC depending on the type of chlorine test. For most chlorine tests it shows up as CC or with test strips that would be in TC (Total Chlorine).

    So if you are soaking regularly every day or two and not for very long then you can have the pucks in a floater handle your bather load. However, this approach won't work if you soak infrequently since the chlorine demand in between soaks is a lot lower than that from a soak. Also, most people don't like soaking in higher chlorine levels and that would be needed if you have a higher bather load. So it's normal to add chlorine after a soak and leave the tabs in a floating feeder (either for chlorine or for bromine) to handle the background dosing in between soaks. So you could still use a Dichlor-then-bleach method augmented with the Trichlor puck in the feeder for background dosing.

    Just remember that Trichlor is not normally used in spas so you need to use a special feeder that slowly doses since Trichlor normally dissolves too quickly in hot water. It is also quite acidic and will lower TA over time so you'll need to add baking soda to maintain the TA level.
    So dichlor is the better choice then. What does the trichlor feeder look like? I have the floating thing with a tube on the bottom where I fill it up with the pucks.
    Sundance Calypso Hot tub 1500 L, 2 pumps, Taylor K-2006 test kit

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    Re: How to get chlorine levels back down?

    It's similar to the bromine feeder that you have (i.e. closed at the top so that it doesn't outgas and harm the hot tub cover), but it can be dialed down a lot to allow for slower Trichlor release. This one is an example feeder that can be used for either bromine or chlorine tabs.
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