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Thread: Chlorine Demand

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    Chlorine Demand

    I have a chlorine demand problem and had a Bioguard demand test done. Of course, test indicated that I need 22 lbs of Burnout 35 to break the demand. Burnout 35 is is Lithium Hypochlorite and about $8 a lb. If I do my calculations right, about 8 gallons of 12.5% liquid chlorine, 11 lbs of 73% calcium hypochlorite will give me the same result. Am I doing my calculations right?
    Darryl - Buffalo Grove, IL
    Royal Fiberglass King Shallow/DE

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    Mod Squad jblizzle's Avatar
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    Re: Chlorine Demand

    Give us some more details about your pool. At least size and type.

    Adding that much FC at once is likely a BAD idea (unless your pool is ginormous).

    Your calculations seem to match pretty close to be the same FC rise.
    Jason, TFP Moderator
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    Re: Chlorine Demand

    I have a 21,500 gallon pool. By my calculations, their numbers create a 43 ppm rise which is a pretty heavy shock but only about 20 PPM more than the recommended shock for my SWG pool.

    Quote Originally Posted by jblizzle
    Give us some more details about your pool. At least size and type.

    Adding that much FC at once is likely a BAD idea (unless your pool is ginormous).

    Your calculations seem to match pretty close to be the same FC rise.
    Darryl - Buffalo Grove, IL
    Royal Fiberglass King Shallow/DE

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    Mod Squad jblizzle's Avatar
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    Re: Chlorine Demand

    What is your current CYA?

    Generally a safe maximum for the FC level is the Mustard Shock level on poolcalculator. If you CYA is 70, you should not go above 39ppm ... of course does not sound like you would go over this much and if the FC demand is high it will drop quickly.

    I think you would be better off following the Shocking Your Pool process. It is safer for your pool and equipment and will get the same job done. The key is frequent accurate testing and adding chlorine ... you very well may need WAY more than their initial recommendation depending on what is going on in the water.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Chlorine Demand

    My CYA is around 60. Note that we are dealing with a Chlorine Lock/Demand issue here not a simple dirty pool. In fact my pool is perfectly clear. My understanding with a chlorine demand situation is that you want to supershock the pool and then watch your chlorine to see how fast it drops. If it drops very quickly, one needs to add more chlorine to keep it at shocking levels to make sure the demand gets broken.
    Darryl - Buffalo Grove, IL
    Royal Fiberglass King Shallow/DE

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    Mod Squad jblizzle's Avatar
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    Re: Chlorine Demand

    Do me a favor and explain what "a Chlorine Lock/Demand issue" is.

    In reality it is a buzz word that pool stores use that means absolutely nothing.

    Your water is clear and something is making your FC drop right? Since your CYA is not zero, it is likely do to something in the pool breaking it down (you could do an Overnight FC Loss Test to confirm that something is in the pool) and not the sun.

    In reality, what you just described is ALMOST the shock process. You have to just keep adding FC until you have consumed whatever is in your pool. The process is exactly the same for a green swamp, a problem with ammonia, and whatever your issue it.

    If you would like further info on what we would suggest you do, post up a full set of test results.

    At some point you need to decide if you are going to continue to trust the pool store to spend you money wisely, or if you would like to take control and understand you pool and spend less money leaving you more for refreshing beverages.

    For example, why would they recommend the MOST expensive chlorine product out there (lithium hypo)? Think it might be to make money?

    My recommendation:
    1. Stop going to the pool store
    2. Order one of the good recommended test kits
    3. Read Pool School a few times
    4. When you get your kit post a full set of results and then go through the shock PROCESS
    5. Enjoy the tasty beverages you bought with your saved money by your sparkling pool.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Chlorine Demand

    I have a good test kit. I had a Bioguard demand test done using the Bioguard demand test equipment. When this happened two years ago, the Bioguard test gave me the right amount of chlorine and it broke the excess demand completely. All I was trying to ask was whether my calculations were right on the different types of chlorine. I am not planning on throwing it all in at once. The issue I am having is exactly that my chlorine is dropping over night. Other than the fact that the store wanted to sell me Lithium Hypochlorite, I trust that the Bioguard demand station is giving an aggregate number and will shock using the recommend amount of chlorine in a minimum of two applications spread over a few hours testing in between.
    Darryl - Buffalo Grove, IL
    Royal Fiberglass King Shallow/DE

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    Mod Squad jblizzle's Avatar
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    Re: Chlorine Demand

    Fair enough.

    Let us know how it works out. I just can not see how it could "calculate" the require amount of FC. It really does sound like you are ALMOST doing the shock process. You may find that if you tried only adding the required amount to stay at shock level, your maintenance and FC demand may reduce in the future.

    You know where to find us if any other questions come up.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    JasonLion's Avatar
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    Re: Chlorine Demand

    Lithium Hypochlorite is the most expensive form of chlorine available. Bleach will be much less expensive, though more carrying.

    There is no such thing as "Chlorine Lock". At best that is a really misleading name for what is going on. There are cases when you do need to use a great deal of chlorine before you will be able to maintain an FC level, and in some of those cases it is possible to get a rough idea of how much chlorine that will take. However, you can never get an exact number.

    I don't recommend adding that much chlorine all at once. The calculations are never exact and extremely high FC levels can cause damage. It is best to add it over several hours, with occasional checks of the FC level to see if you are done, which really amounts to doing exactly the same thing as if you were shocking the pool using the process described in Pool School.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Chlorine Demand

    It seems that all these "brand methods" are just a bunch of marketing to make people think it's something different than the same stuff any pool store will sell (made by any manufacturer). With all the same problems.

    I'll admit I was hesitant to switch over from the pool store method in my first year and everything was going ok. I kept thinking, I'm sure this works, but it seems to strange to me (BBB method). Last season (I had been reading the forums) and I started off seeing what the pool store said and I would make my own decision from there. Well - bad choice, I didn't do a good job. Ended up taking back half and I'm still sitting on the other half since I refuse to use it. After getting my test kit (there are only two acceptable kits, TF100 and Taylor K2006) I started BBB and within 2-3 weeks I realized things were not "Ok" when I was getting pool stored, my water had been cloudy and I didn't know any better. Plus I was wasting TONS of money and putting chemicals in the pool that were completely unnecessary.

    Now I'm reading about other people more or less going through the same thing, but not switching to BBB and trying to make the pool store method work without using the CYA / Chlorine relationship chart and one of the two test kits. I don't expect everyone who joins here and asks a question to be easily convinced and switch over to BBB immediately, but it's the only way to go!

    Read the posts by regulars on this forum and look at their pictures, there really isn't any other way to maintain a pool.


    Quote Originally Posted by jblizzle
    5. Enjoy the tasty beverages you bought with your saved money by your sparkling pool.
    You left off lifetime. Lifetime of tasty beverages you bought with saved pool store money.
    Aaron
    [ Vogue Vectra 24' AG | Hard plumb: Hayward Power-Flo Matrix 1HP 2-speed, 27" sand filter & Pentair MiniMax 100 NG | Taylor K-2006 | Central IL ]
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