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Thread: Pool Store said I have "Chlorine Lock". Mustard Algae.Help!

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    Pool Store said I have "Chlorine Lock". Mustard Algae.Help!

    I have mustard algae so I double-shocked the pool. It turned from blue green to milky blue with yellow algae on bottom. I took a water sample to the pool store the day after I shocked it. Here are my pool store readings:
    FC: 6.15
    TC: 6.15
    TA: 35
    CA: 233
    CYA: 103
    PH: 8.0


    Please note that last week everything was normal except the CA, which the pool store told me to add more of.

    Here is what the pool store told me:
    "You have CHLORINE LOCK!!!! Do not add any tablets for 30 days! It looks like you have been using chlorine from WALMART!!! I said, "no, I have been using only what I bought here" They told me to use "another source" of chlorine. (??) I told them that my numbers were normal until I added the shock that I bought from them. They also told me my CYA was too high and I would probably have to drain the pool and put new water in it. They also told me to add copper algaecide, which I told them I am scared of because it might stain my liner. They replied, "But the kind *we* sell is copper CONTAINED. It won't stain the liner." (Note; I didn't buy any.)

    In the meantime, I still have yellow algae that I have been brushing and vacuuming to waste, but it doesn't seem to be going away.

    Can someone please tell me what to do? And what is "chlorine lock"?? Will I really have to drain my pool?

    Thank you in advance for your help.
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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    Butterfly's Avatar
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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    The best thing you can do for your pool is purchase a good test kit and do your own testing. That will put you in control of the pool. The fav around here is the TF100 from TFTestKits.net. link in my sig.

    Pool store testing is not reliable. They should not have suggested increasing the CA (which I assume they mean calcium?) as it is not needed in a vinyl pool. money wasted there.

    Good for you for not purchasing the copper based algaecide!

    The CYA test is pretty accurate up to about 90 and then around 100 ppm is not really accurate. CYA tested at 100 or over will read as 100. In order to confirm the CYA, you should do the 50/50 dilution test. That will indicate whether CYA level is closer to 100, 150, 200, etc.

    There are many issues with the test results numbers, but if the CYA is indeed high the only way to lower it is to replace water. That is the first thing to fix.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Chlorine lock is a made up term. Often, as is your situation, it means you have too much CYA stabilizer in the water. Shocking levels at that point are very high for its the unstabilized chlorine that does the work.

    The solution is multi-part in nature. The first part is to get the CYA level down via dilution, to the point your chosen way of adding chlorine. If you are in Texas, that might be 80 for a cell and 50 for tabs. Here in NJ, lower levels can be used. Once the CYA level is lowered, getting a pool dosed with the proper amount of bleach or 10-13% chlorinating liquid is a lot easier to do and to test.

    Diluting a pool may need to be done in steps as it often isn't a good idea to drain more than 1/3 to 1/2 of a pool at a time before refilling. Then use the following to get rid of the MA, if that is what it is:

    pool-school/mustard_algae

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Thank you for your replies. I do have the TF100 test kit, but my test numbers are always different from the pool store (I compared about 3 different times), so I thought maybe I was doing the testing wrong. But I am slowly realizing that I need to stop relying so much on the pool store and to trust my own testing and start doing the BBB method. It just seemed so much easier to put tabs in the skimmer rather than hauling home all that bleach and then having all those bottles to haul to the trash.

    I'm done with the pool store. I just went to Walmart and bought 12 gallons of bleach to have on hand in case you guys tell me I should add it.

    I just performed a test:

    CYA 90
    PH 7.5
    Chlorine drop test 5.5 FC; no cc's
    TA: 180 (the pool store also told me to add alkalinity increaser, but I didn't. )

    The reason I got algae is because I went out of town for 2 days and when I got back, I had no chlorine in the pool.

    So now I have more questions:
    1. How do I get rid of the algae? I can't tell whether it is dead or alive. There is a yellow film on floor and side. I've been brushing every 3 hours. I can see the bottom of the shallow end but not the deep end. I'm assuming that I have enough chlorine to kill it. Or do I add some bleach?
    2. I live in North Carolina. Since *my* CYA reading was 90,do I still need to lower it?
    3. What should I have done when I saw that my pool didn't have chlorine, in order to prevent the algae?

    Thank you, Thank you! I deeply appreciate all of you!

    Ann from NC
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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    Mod Squad Bama Rambler's Avatar
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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    With a cya of 90 I suggest you go ahead drain some water to lower it to about 50 ppm or so.

    Once you've done that, you need to raise the FC with bleach using the pool calc to figure how much to add.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Point the returns up to break the surface of the water. If you can find it, a return mounted fountain is also a good way to aerate the water which will reduce the alkalinity. Another alternative is to add some acid to reduce the alk. Note that this will likely lower the pH some but using bleach should counter that.

    Tabs don't belong in the skimmer, ever. The should go in an erosion feeder. Periodically diluting the pool is a part of normal maintenance with tab fed pools because of the CYA they add.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Quote Originally Posted by dejavu
    So now I have more questions:
    1. How do I get rid of the algae? I can't tell whether it is dead or alive. There is a yellow film on floor and side. I've been brushing every 3 hours. I can see the bottom of the shallow end but not the deep end. I'm assuming that I have enough chlorine to kill it. Or do I add some bleach?
    2. I live in North Carolina. Since *my* CYA reading was 90,do I still need to lower it?
    3. What should I have done when I saw that my pool didn't have chlorine, in order to prevent the algae?

    Thank you, Thank you! I deeply appreciate all of you!

    Ann from NC
    The only way to get rid of the algae is to get chlorine in the pool to kill it and then let the filter clear the pool. You really need to get your CYA down to about 50 to be able to do this. That means a 45-50% water change. I went through the same thing last year when my CYA was approaching 200ppm. If you elect to do the water change, you might want to contact your pool builder and see what he/she recommends are far as dropping the water level in the pool so the liner does not shift or pull away from the walls. I have an 18x36 vinyl pool and when I did my water change I kept 9-12" of water in the shallow end before refilling.
    18x36 Vinyl In-ground w/roman ends 27,400G, Hayward 3/4hp with 300# sand filter. Hayward heat pump heater

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Quote Originally Posted by dejavu
    .....
    But I am slowly realizing that I need to stop relying so much on the pool store and to trust my own testing and start doing the BBB method. It just seemed so much easier to put tabs in the skimmer rather than hauling home all that bleach and then having all those bottles to haul to the trash.

    I'm done with the pool store.

    ....
    Dingdingdingding!

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Great opportunity to gain confidence with your test kit, if you can solve this problem (and we know you can) using your own test kit you'll be able to maintain your pool by yourself from here on.
    20' X 54" Sharkline Matrix Resin AGP, 9400 Gallons, Sta-Rite 1 HP Dynamo Pump, 150 lb Pentair Sand Filter, Gorilla Pad,
    Foam Cove, Taylor K-2006 kit, BBB method, 8'X20' Fafco Sunsaver Hard Plumb, DIY Fountain, Margarittaville Fiji


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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Update:
    I still have algae, but I think it is dead because it doesn't appear to be growing, it just keeps coming back into the pool from the return jets and settling on the bottom of the shallow end. In the deep end, it looks like it is suspended in the water and not settling to the bottom. (however, I can't see the bottom of the deep end) I have been brushing it everyday. How long will it take to filter it out? I am getting very discouraged.

    I went to the pool builder/store (a different store than I went to before, since the other store told me all that baloney about "cholorine lock")as "BadoleRoss" suggested to ask how about draining pool halfway to decrease cya. They said I don't need to decrease my CYA. And they told me again to add copper based algaecide. They also said if it stains the liner, they have another chemical that will get the stains out. (note: I didn't buy it. again)

    So I came home and drank a margarita while sitting poolside in a daze.

    Then I set the pump on waste and pumped out water to the bottom of the rectangle on the skimmer. Then I filled with water. Then I did that again. I aimed the return jets to break the surface of the water.

    Here's my numbers ( tested them myself):
    FC 13
    no cc
    CH 300
    PH 7.8
    TA 190
    CYA 90

    Since I think the algae is dead, how do I get out all the suspended particles out of the pool? I've been brushing every morning before work and every afternoon when I get home. Since the algae looks dead (I'm not really sure that it's dead, but I think it is), is it necessary to drop the cYa levels?

    Thank you everyone.

    Ann from NC
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Try the overnight loss test. If you pass, then the algae is, indeed, dead.

    If that is so, then make sure you have some circulation in the deep end - the drain or point a return jet down there - and consider adding a bit of diatomaceous earth to your sand filter to catch the fine stuff.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Ann - I'm also in NC and I have a CYA of between 50-60 and wish it was a little lower.

    My pool was from a house purchase (my father-in-law bought it) and came with high CYA and CH and I got Pool Stored into buying a ton of TA Increaser only to end up about where you are (TA 180). Slowly by raising the PH with aeration and lowering it with acid I got the TA into the recommended range for my pool. CH is still higher than desired and so is my CYA but the pool is sparkly and trouble free.

    PM me if you are anywhere in the Charlotte area and I'd be happy to compare notes.
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Don't worry so much about the TA levels. Only worry about the PH. Lower levels of TA help keep the PH in check, but in a vinyl pool doesn't affect much more. Keep the PH at 7.2-7.8 and the TA will come down as you lower the PH.

    You biggest # is still the CYA. Lowering that will save you a huge headache. If your water is cloudy, you still need to shock. Shocking with a CYA of 90 means the FC needs to be kept at 23ppm at all times. A cya level of 50 means the shock level is only 16. Ditch the pool store as they're the ones that got you in your position in the first place. Trust your readings, lower the CYA, start shocking.

    Then the margaritas will taste wayyy better.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    UPDATE: Pool is blue but cloudy. Dead algae is gone. Can't see bottom of deep end. Any ideas how I can get it clear? Thanks!

    Here are my numbers:
    FC: 25.0
    no cc's
    PH: 7.5
    TA: 200
    CH: 300
    CYA: 90
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    If you brushed all the surfaces, chances are the dead stuff is in suspension. Keep the filter running and chlorine up. If there is little improvement after 48 hours, floc it. That will cause anything in suspension to drop to the bottom. Vacuum that to waste.

    Then dilute the pool. Expecting a tablet fed pool to keep an adequate FC level with that high a level of CYA is not reasonable.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    I agree with the above posters...it would be better if you reduce your cya level down, preferably down to 50 ppm.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    If a pool store told you that a CYA of 90 is OK, then they either do not know anything about water chemistry or they are trying to rip you off. I have found a lot of pool builders know about building, but very little about maintaining. Most of us on this forum were driven here by bad advice from pool stores. They can't even test water correctly. In my area their "free" water testing is a scam to sell chemicals that you do not need. Further evidence of this is that they only sell inadequate test kits. They want their customers dependent on them so that the customers have to come in the store and they get a chance to sell something. It is their business model.

    You have received a lot of advice here - some of it conflicting. While you clearing the pool I suggest you go back to basics. Read and study Pool School and learn how to use the pool calculator. It will teach you all the basics about maintaining a pool builder should teach, but few do. As you read post questions about anything you do not understand. Also since you said you do not trust your test results, post questions about why you do not trust them. I assume you are following the instructions on the lid of the kit to do your tests and not sure you are doing it correctly - so ask about anything that is confusing. We will help you understand.

    Now if I were in your situation, the first thing I would do is get my CYA down to 40-50. The only way you can lower CYA is to replace pool water with water that does not have CYA in it. The amount you have to replace is determined by the percentage you want to reduce the CYA. In your case you have a CYA of 90 and if you replaced half the water you would be approximately 45 which would be perfect. So the first thing to know is how many gallons does you pool hold. Do you know that? If not, you can call the builder or estimate it with the pool calculator (at the bottom of the calculator) Once you know that you know how much you need to replace. Another approach is to guesstimate where half way is by looking at the pool and then since you drained to the bottom of the skimmer before how many of those drains you would have to do to get drain halfway. Then do as you did drain and fill then drain and fill. When you think your close test for CYA and stop when you get under 50. Now that is the first thing I would do. Then with my new CYA number and my new shock FC goal I would bring it up to shock level using bleach or liquid chlorine. And do the overnight chlorine loss test as described in pool school. I would keep shocking until I passed it. I would also be running the pump 24 hours a day and backwashing when my pressure went up 25%. I would not flock until I passed the overnight test and only then if the pool was still cloudy. I would also continue brushing and I assume that since you have been brushing there are no leaves or other stuff in the pool. If there is get it out as it will eat, so to speak, the chlorine thus taking longer to kill off any algae.
    Hope this helps. Remember we are here and will answer your questions.
    Larry in Texas

    Above ground 7,700 gallons, 19 inch sand filter ( 2 sq. ft.), Liquidator, and a WaterWay Hi-Flo Pump with an A.O. Smith 1 hp SF 1.0 motor.

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Thank you all! You have all been very very helpful. I have performed the overnight test and all algae is dead. There are no leaves or debris in my pool.

    I am now confident with my testing results since I have tested, tested and re-tested. I feel like I know what I'm doing now EXCEPT the CYA test. How can that be accurate since I have alot of suspended algae in cloudy water? It seems to me that the cloudy water would make the black dot disappear faster simply because the water is cloudy; therefore, making the reading inaccurate. Just wondering....

    I was really, really hesitant to drain and refill my pool, but I trust all you guys,(everyone seems to agree that the cya should be lowered) so I'm going to start that process tomorrow morning.

    Oh, and one more thing: The pool store told me my phosphates were high (1,000) and said it is because I have well water. He wanted me to buy some phosphate remover and clarifier. He explained that algae loves phosphates, and I need to get it out. He also said it would make my pool cloudy, but not to worry because the bottle of clarifier would get it clear again. (NOTE: i didn't buy those chemicals). I didn't have phosphates 2 weeks ago when they tested it!! I have never ever had phosphates in my pool. Do you think the pool store has a button they push to make stuff like that appear on the test printout? Hopefully, when I start draining and refilling my pool, it won't get more phosphates. I don't think there is a test in my tft testkit that will test for phosphates...
    (I couldn't resist taking a water sample to the pool store when I went to buy some diatomaceous earth a few days ago).

    Thanks again for all your help. After all this hassle, trust me, I will never ever ever let my chlorine level get low, or my cya level get high ever again!
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    The algae or other cloudiness in your pool has no affect on the CYA test. Pour a sample of the pool water in your view tube and you will see it adds no cloudiness.

    Disregard phosphates....they don't matter.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Pool Store said I have "Chlorine Lock". Mustard Algae.H

    Thanks, Dave.
    18' x 36' Vinyl In-Ground Pool
    New liner installed 5/14/11
    Hayward Sand Filter Super Pump VS
    North Carolina

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