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Thread: Can't get rid of Algae.CYA is high and already drained once

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    Can't get rid of Algae.CYA is high and already drained once

    I bought my house over a year ago, first time pool owner, and right after was told to drain the pool since CYA was very high and chlorine was locked low and it would not change not matter how much I shocked.

    Bye the end of the summer the CYA was again extremely high and I was having huge fights with Algae. Now the Algae are starting to form again since water temperature is starting to increase – I am in Texas. CYA is still very high.

    Do I need to drain again? This seems very frustrating and expensive to do it every year.

    My pool is 21,000 gallons and I use mostly Leslie’s products:
    3" Chlorine Tabs
    Shock: Started with Chlor Brite but switched to Power Powder Pro to see if it would help but it didn't make a difference
    DE

    I also tried using Phos Free last year but it didn't seem to help. Every time I got Algae I treated with a ton of Shock and Green to Clean and it would go away but come back after 2 weeks.

    Thanks a lot! I really appreciate your input!
    21K gal, blue color plaster, DE filter

  2. Back To Top    #2
    JasonLion's Avatar
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    The amount of chlorine you need to use goes up as the CYA level goes up. At very high CYA levels it becomes very difficult to use enough chlorine to keep the water safe. The 3" chlorine tablets contain trichlor, which has a significant amount of CYA in it. If you keep using them you will always have CYA problems. Chlor Brite is dichlor, which also contains CYA. Power Powder is cal-hypo, which contains calcium, which isn't as bad but can also cause problems eventually. I recommend using bleach it doesn't add any CYA or calcium.

    The only practical way to lower CYA is to replace water.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Can't get rid of Algae.CYA is high and already drained o

    Quote Originally Posted by mrdaniel76
    I bought my house over a year ago, first time pool owner, and right after was told to drain the pool since CYA was very high and chlorine was locked low and it would not change not matter how much I shocked.

    Bye the end of the summer the CYA was again extremely high and I was having huge fights with Algae. Now the Algae are starting to form again since water temperature is starting to increase – I am in Texas. CYA is still very high.

    Do I need to drain again? This seems very frustrating and expensive to do it every year.

    My pool is 21,000 gallons and I use mostly Leslie’s products:
    3" Chlorine Tabs
    Shock: Started with Chlor Brite but switched to Power Powder Pro to see if it would help but it didn't make a difference
    DE

    I also tried using Phos Free last year but it didn't seem to help. Every time I got Algae I treated with a ton of Shock and Green to Clean and it would go away but come back after 2 weeks.

    Thanks a lot! I really appreciate your input!
    you sound like me. we bought our house 1 1/2 ago, but because of high CYA and persistent algae and filter problems, couldnt use it last summer. thankfully, i found the BBB method in september and saw how great it worked, unfortunately it was too late to really get much swimming in. this year, i plan on doing nothing but the BBB method, and i think you should look into it here: here and here.

    like jasonlion stated, the tablets and shock both have CYA in them, and as long as you are using them, you are contributing to the rising CYA levels. read up on BBB and go ahead and switch to that method. the only thing i really use the pool store for anymore is to get stabilizer and they have the best price for muriatic acid, oh and i have them run the tests on the pool, just ignore what they suggest for chems you need. just beware that if you tell the pool store that you are using bleach, they are going to tell you how bad it is for your pool, just remind them that they are selling "bleach" but label it sodium hydrochloride (they sell it in 12.5% concentrate bottles out front for ~$13/4).
    30,000gal In-ground Gunite Pool DE filter
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    BBB method all the way - Newb, like to absorb info and chatter, but take the experts' advise

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    Re: Can't get rid of Algae.CYA is high and already drained o

    Quote Originally Posted by IkeRay
    you sound like me. we bought our house 1 1/2 ago, but because of high CYA and persistent algae and filter problems, couldnt use it last summer. thankfully, i found the BBB method in september and saw how great it worked, unfortunately it was too late to really get much swimming in. this year, i plan on doing nothing but the BBB method, and i think you should look into it here: here and here.

    like jasonlion stated, the tablets and shock both have CYA in them, and as long as you are using them, you are contributing to the rising CYA levels. read up on BBB and go ahead and switch to that method. the only thing i really use the pool store for anymore is to get stabilizer and they have the best price for muriatic acid, oh and i have them run the tests on the pool, just ignore what they suggest for chems you need. just beware that if you tell the pool store that you are using bleach, they are going to tell you how bad it is for your pool, just remind them that they are selling "bleach" but label it sodium hydrochloride (they sell it in 12.5% concentrate bottles out front for ~$13/4).
    IkeRay, did you drain your pool before switching to the BBB method? Did you find it to be a lot more work than the standard method? I am trying to determine if switching to the BBB will eventually lower the CYA or if absolutely need to drain it again.

    I've been trying to learn everything I can on this great forum about the BBB method. I am still a bit confused but there is a lot of great info on this forum and I am reading as much as I can.

    Thanks again!
    21K gal, blue color plaster, DE filter

  5. Back To Top    #5
    JasonLion's Avatar
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    The need to drain the pool, partially or fully, depends on exactly what your current CYA level is. It is possible to manage a pool with BBB up to a CYA level of about 90. Above that it is sort of possible but it starts to get significantly tricky. If your current CYA level is 80 or 90 then you will be fine if you are aware of the proper chlorine level and stop using products which add more CYA. If your CYA is say 300 then you will have serious problems unless you replace most of the water. With levels in between you can get away with various percentages of partial water replacement.

    CYA will come down slowly over time if you stop adding CYA to the pool. There is always some natural water replacement from rainfall and splash out that will bring it down and if your filter requires backwashing that will also bring it down.

    If you post a full set of water test results and tell us what test kit (or pool store) you used to do the testing we can give you more specific advice.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    I've just took my water to the Warehouse Pool Supply store for testing and here are the results:

    Free Chlorine: 0.6
    Total Chlorine: 0.6
    Combined Chlorine: 0.0
    PH: 8.2
    Hardness: 235
    Alkalinity: 135
    Cyanuric Acid: 180

    They told me to drain 64% of the pool. What do you think? Can I drain it on one go or do I need to do it multiple times? Are there instructions anywhere on the method to follow for draining and startup afterwards?

    I've been reading the BBB method and it looks like I need to add Bleach everyday if I don't use the tablets. How much bleach is needed on a daily basis? I've used your calculator and it told me to use 148oz of 6% bleach but I am assuming this is just to bring it to the right level and not a daily dose.


    Thanks a million. You guys are great!
    21K gal, blue color plaster, DE filter

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    JasonLion's Avatar
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    Your PH is too high. You always want to keep PH below 8.0.

    I would replace anywhere from 50-75% of the water. In almost all cases you can drain the pool till there is one foot of water left in the shallow end without problems (unless you have a high water table). That is probably more than you will need to drain so you should be fine. If you do have a high water table you can drain at the same time as you are filling, leaving the water level more or less constant. That will take more water (about 1.5 times as much water) to have the same effect but is often simpler and a must with a high water table.

    I suggest you think about getting a good test kit. Having your own high quality kit is the best investment in your pool you can make. I suggest the TF Test Kit, see the link in my signature, the Taylor K-2006 is also good.
    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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    Daily Dosage?

    I am planning on draining this weekend and switching to the BBB method. Per your suggestion, I've also just ordered the TF Test Kit and hopefully it will be here for the weekend.

    I've read most of the BBB threads but I am still confused about the daily dosage of bleach. Do I have to test the water every day and use your calculator to adjust the chlorine level? Or is there a daily dosage used no matter what?
    Is it done every day throughout the year or not so much needed when the weather is cold? If I get algae and have to shock, what is the dosage for a 21,000 pool?


    Thanks again!
    21K gal, blue color plaster, DE filter

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    Re: Daily Dosage?

    Quote Originally Posted by mrdaniel76
    I am planning on draining this weekend and switching to the BBB method. Per your suggestion, I've also just ordered the TF Test Kit and hopefully it will be here for the weekend.

    I've read most of the BBB threads but I am still confused about the daily dosage of bleach. Do I have to test the water every day and use your calculator to adjust the chlorine level? Or is there a daily dosage used no matter what?
    Is it done every day throughout the year or not so much needed when the weather is cold? If I get algae and have to shock, what is the dosage for a 21,000 pool?


    Thanks again!
    first to answer your question from earlier, yes i still had to drain and refill some, but i suggest you go to leslie's pool supplies before you do anything. the first time i went into warehouse, they gave me similar results, CYA 150 ppm, i think they are bad about not replacing their chems because the other guy that went in the same time as me got 150ppm cya, odd? so i did a drain and refill (only did 20% of the pool water) and took a sample into leslie's pool, suddenly my CYA levels were 55ppm. question to the guru's, would a high pH reading throw off CYA levels like a high chlorine reading would?

    the best way to do the chlorine, if i have been reading it correctly, is to check with the calculator every day after measuring. im sure, after some time, it will get to a consistent point where you pretty much know how much to add and when. as far as bleach goes in our area (houston that is) i have found wal-mart is ~$1.65/gal and kroger's has it on sale right now for $1.00 for 96oz (3/4), so $1.33/gal (employee discount=10% off, so i got it for $1.20/gal), and warehouse pool's has 12.5% concentrate for ~$13/4 (or ~$1.62/ 6% concentrate). which part of town are you in, im near spring.

    not as much chlorine is needed when the water is cool, especially when it drops below swimming comfort. at that point, you not having a bather load to contribute to the chlorine usage. im sure it cuts in half or so during the winter months, so that helps out.

    if you have an algae bloom, per the calculator, you need to add 4-5 gal of 6% for your 21k pool, and that is assuming a cya of 30-40.

    i suggest you get a new reading from leslie's, post it if you would, and then get the CYA into the 30-50 range.
    30,000gal In-ground Gunite Pool DE filter
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    BBB method all the way - Newb, like to absorb info and chatter, but take the experts' advise

  10. Back To Top    #10
    tagprod's Avatar
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    it's kind of hit or miss with leslies and warehouse. In the willowbrook area (249 and 1960) I think warehouse is better than my local leslies but my own testing is the best.

    I would do several partial drain/refills to get your CYA down. We do have a high water table around here.
    Brian
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    MrDaniel,

    A 20 % drain will get your CYA to roughly 145....too high

    A subsequent 20% drain will yield CYA 115...still too high

    Subsequent 20% CYA 92...still too high

    However a 50% drain will get you about 70ppm CYA......pretty close to where you want to be. That's the course I would take.

    PS - The only Texas order for the test kit I received over the weekend was to Cypress, TX. If that's you, it will ship this afternoon and you should get it by Thursday. If that's not you, let me know and we'll get it straightened out and still in today's shipping to get it to you by the weekend. Thanks.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Dave, Yes I am the one from Cypress who ordered yesterday. Thanks for the fast shipping.

    I think the Warehouse reading is pretty accurate on my CYA level. I've already had it read multiple times in the local Leslie's and got the same reading. It started going through the roof mid last summer, where the chlorine level locked high and the fights with Algae started. I've read somewhere that it sometimes goes down over the winter and I was hoping for that but it looks like I have to go through the draining route again.

    At least now I am hopeful that switching to the BBB method will stop the CYA mess. And it might even be cheaper overall. I paid over $1,000 in chemicals on my first year with the pool.

    Thanks guys!
    21K gal, blue color plaster, DE filter

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    Quote Originally Posted by mrdaniel76
    Dave, Yes I am the one from Cypress who ordered yesterday. Thanks for the fast shipping.
    At least now I am hopeful that switching to the BBB method will stop the CYA mess. And it might even be cheaper overall. I paid over $1,000 in chemicals on my first year with the pool.

    Thanks guys!
    Holy cow! You are right! Your chemical bill should go WAY DOWN! ....and Welcome to TFP!


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  14. Back To Top    #14
    JasonLion's Avatar
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    Yes, you want to test the chlorine level every day and add enough chlorine to bring it back up to your goal level. At first this will mean using something like my Pool Calculator to do the calculation of how much chlorine to add. But once you get some experience you will find that about the same thing happens day after day and you will start to know what to do without needing the calculator.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    At least now I am hopeful that switching to the BBB method will stop the CYA mess. And it might even be cheaper overall. I paid over $1,000 in chemicals on my first year with the pool.
    Yeah, in a 21k pool, I'd guess you'll certainly spend less than $400 and probably less than that. Don't be intimidated by the frequent testing. As Jason said, it will become second nature and you will understand what to add to your pool with hardly thinking about it.

    Remember, BBB is not a "secret" method but simply understanding the important parameters of pool water chemistry, testing your pool for those parameters, and then using a lot of ordinary household products to adjust your pool water.

    You're in for a "trouble-free" summer. Keep asking lot's of questions and stay very active on the forum.
    Dave S.
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  16. Back To Top    #16
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    Quote Originally Posted by duraleigh

    and then using a lot of ordinary household products to adjust your pool water.
    And remeber, those "ordinary household products" are exactly the same ones the pool store is selling for a lot more money in a different package! I know, I work in one!

  17. Back To Top    #17
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    Quote Originally Posted by tagprod
    it's kind of hit or miss with leslies and warehouse. In the willowbrook area (249 and 1960) I think warehouse is better than my local leslies but my own testing is the best.

    I would do several partial drain/refills to get your CYA down. We do have a high water table around here.
    yeah, the warehouse pool in the willowbrook district is the best warehouse pools around, better than the leslie's in my area as well. i have been to the warehouse pools on 529&hwy6 and the one off 290, and the 249 one is the best one.

    such a small world, all 3 of the texas people who posted in the thread are in north houston suburbs.

    and i was told because of our high water table, we shouldnt drain more than 20% at a time.
    30,000gal In-ground Gunite Pool DE filter
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    BBB method all the way - Newb, like to absorb info and chatter, but take the experts' advise

  18. Back To Top    #18

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    I just wanted to add that if you are in the middle of an algae bloom, that can register a inaccurately high CYA level. I tested CYA when I had a green swamp on my hands (and thought a partial drain was on my to do list) only to learn later that our pool's CYA level was really a lot lower than I thought.
    17K gallon in-gound pool, black plaster, Polaris 380, cartridge filter system

  19. Back To Top    #19
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    Just to jump in:
    Last year a friend of mine, who has a pool, had very irritating pool water. Tasted and felt very strange, and made my daughters skin red and irritated. This friend just throws pucks into the chlorinator... all the way to the top. She doesn't test her water hardly at all. Just pH and Cl. I'm thinking that the water was 'strange' because of high CYA and/or the low pH from using pucks.

    So, did your water last year have a strange feel to it? Burn? Irritate?

    Just my own little anectodal poll.
    CaryB
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  20. Back To Top    #20

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    No, no weird smell or anything. The water was always great other than the algae that would start every now and then...
    21K gal, blue color plaster, DE filter

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