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Thread: Getting my pool right and moving to BBB...questions, of cour

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    Getting my pool right and moving to BBB...questions, of cour

    First off...FABULOUS site! Great info and great moderators from the reading I've done.

    I've got a pool that algae growth is a constant issue. I'm in South FLorida, so needless to say, temps run in the upper 80's to upper 90's much of the year, and now...well, **** comes to mind. I know that plays a roll.

    My pool is a marcite finish inground and volumes out to around 19K gallons. I've got a canister filter/paper cartridge as well as a chlorine tablet dispenser in-line. I currently have been running the pump about 8 hours a day, but from what I've read, need to bump that to at least 12 (24/7 until it's right..I know). I have a Hayward Navigator automatic cleaner ( but not for long...more trouble than it's worth lately). I seem to consistently have an algae growth issue. If I don't brush a couple of times a week, its noticeable. Brushing of course yields cloudy water...all leads to an underused pool.

    With that said, here is where I'm at. I cleaned the filter, vaccuumed and brushed, and cleaned the filter again last night. I added 2.5 gallons of the pool-store chlorine (Sun Coast brand if that helps). I let the pump run all night and day. I took water in to be tested today (buying a test kit as soon as funds are available to get a good one):

    TC=0
    FC=0
    CC=0
    Stabilize (that's CYA right?) = 0
    pH=8
    TA=80
    CH=230

    Well, I think it's obvious why at this point I have algae 0 chlorine and 0 stabilizer. I use chlorine tablets with stabilizer in them..I thought that was sufficing. Guess not.

    They called for 7.5lbs stabilizer, 2.2 cups acid, and 2 gallons of their chlorine. I cleaned the filter, brushed, cleaned the filter and then I added the stabilizer.

    Then I went to the pool calculator and the best guess CYA chart. I need to put my pool into shock, right? If I target 50 CYA (is that a good value for me?), then my shock FC needs to be 20, right? The best guess chart also suggests to lower the pH to around 7.2 to make the chlorine more effective. Based on the calulator, I need about 1 qt + 1cup of acid to get there. I did that. I'm going to check the pH in a few hours and see where it's at before moving on to adding the bleach (which I also bought tonight along with baking soda).

    The calculator says to get my pool to FC=20, I need about 6 gallons of bleach. Sound right? Should I add this all at once or some now, check it, some more later or does that defeat the purpose of shocking it?

    From what I've read, I need to maintaining the shock level daily until my FC is "Stable." Can someone define that please? How much of an FC drop overnight is considered stable? Once I reach that point, do I simply let my FC drop down to the recommended 5.7 value in the best guess chart (for CYA=50). Should I not be letting anyone swim until then? At what point do I bring the pH back up to 7.5? I also need to bring the TA up, so I'll be adding baking soda which will bring the pH up, right?

    I think that's all for now Thanks VERY much!!

    So, with all of that said, I'm I on the right track?

  2. Back To Top    #2
    JasonLion's Avatar
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    I hope the CYA/stabilizer test was right. If you have been using trichlor tablets and have algae the CYA level is usually very very high. Pool store testing can occasionally be remarkably unreliable.

    You should run the pump 24/7 while fighting algae, but there is probably no need to change your normal day to day run time away from 8 hours a day.

    To see if the FC level is stable you test the FC level in the late evening and again first thing in the morning. If the two tests are the same, or very very close, then the FC level held overnight and you have killed all the algae.

    When shocking you want to bring the pool up to shock level all at once, then test the water and add more chlorine as needed to bring it back to shock level as frequently as practical, up to once per hour.

    Don't worry about PH and TA right now. Wait till all the algae is gone and the pool is clear.

    No one should swim while you have algae.

    By and large you are on the right track. Do a little more reading and you will have figured it out completely.
    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

  3. Back To Top    #3
    Thanks Jason. I'm actually going to take the water in again the morning and hvae them rerun the tests now that I've added the stabilizer and acid. From that reading, I'll start adding bleach.

    Once I kill all of the algae, my FC will be up around 20 since thats what I'm targeting and it will have stabilized there over night, right? At that point, should I wait for it to drop to the 5-6 range before doing anything else or can I start in with the other tests and chems?

    Also, just realized I was saying I was looking at the best guess chart when it was actually the chemgeek chlorine/cya chart.

  4. Back To Top    #4
    I took the water in this morning. The CYA was up to 50, which was my target with the amount of stabilizer I added. So that's a good start. I was a little puzzled though. My FC tested out to 3 this morning after adding NO chlorine from 0 last night (only added acid: pH down to 7.1 and stabilizer). Would that bring the FC up or were one of the tests off?

    I went with the FC=3 as close since I did show some chlorine in my old test kit last night. Based on the calculator, it says I need 4 gallons of bleach to get to FC=20, so that went in a little while ago. I'm going to test again this evening to see where the FC is at and adjust with bleach as needed.

    Sound right so far?

    HOPEFULLY will be getting my test kit this weekend.

  5. Back To Top    #5

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    Sounds like you're on the right track...nice work.


    The variance in FC points out problem with trusting a pool store to test. They frequently get it wrong and they are inconsistent at just how wrong they get it!!

    As always, trust your own testing...it's the most accurate.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Shelley N's Avatar
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    Contento -

    How did you add your 7 lbs of CYA? It's been my experience that overnight wouldn't dissolve 50ppm of CYA, it can take up to a week. If you have it in a sock or something, you may think about removing it as 50 is probably a good number for CYA there.
    Shelley
    Denver, CO

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    I dissolved it in 1-2 lb increments in a large pail before pouring it into the skimmer and along the sides of the pool. I couldn't get it all to dissolve immediately, but it is now.

    I hope this doesn't mean my CYA is going to continue to climb since there is no way to get it out. I have to drain water to reduce it, right?

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    JasonLion's Avatar
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    Many people experience CYA levels continuing to rise for several days after the initial addition, even if it appeared to dissolve. There is no easy way to lower CYA levels if you added too much, you have to replace water.

    I would be very interested to know what your CYA level turns out to be in six more days.
    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

  9. Back To Top    #9
    my wife took the water in this morning again for another test. Needless to say, she left the store with a good test kit.

    according to the store:
    FC=4
    pH=7.4
    TA=85
    CH=175
    CYA=70

    I'll be testing it myself this evening when I get home and THEN I know I'll be on the right track. if the CYA IS that high, looks like I'll be replacing some water too. Is 50 a good target for me and if so, whould I stabilize the CYA there before continuing with the shock cycle? Do any of the other chems affect CYA levels? What depletes CYA (other than water change) over time?

    Again, thanks to all!

  10. Back To Top    #10
    JasonLion's Avatar
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    CYA between 30 and 50 is the usual recommendation. In areas that get a large amount of direct sunlight, and for pools with a SWG, CYA is typically kept at 60 to 80. So you can manage things up to 80, but 50 is probably better (unless you get a large amount of direct sunlight on the pool).
    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

  11. Back To Top    #11
    I'm in South Florida with no enclosure around the pool..it's like living ON the sun! So 70 might be a good target CYA then?

  12. Back To Top    #12
    Shelley N's Avatar
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    It may FEEL like you live on the sun, but you've got a mile + more atmosphere than I do here in Denver for the UV to travel through before it hits the water. 70 is a fine number to have, you just have to adjust your chlorine levels accordingly.
    Shelley
    Denver, CO

  13. Back To Top    #13
    As of last night, my CYA was about 75 . The good news is that my pool is too full right now anyway, so I'll be draining some. However, does draining alone recude CYA or will I need to drain to my ideal level, then drain s'more and add back new fill water to drop it? The question then of course is how much do I drain/replace?

    Problem next: the test kit my wife bought me doesn't test HIGh FC...nor does the kit the store uses NOR do they sell one. Does this sound right? Other than online, is this somehting I should be able to get over the counter somewhere (Home Depot, other pool store, etc)?

    For the CYA test in this kit, it's a "clarity" guestimate (add the mixture until the black dot at the bottom "just disappears"). Ok, so I add the mixture of water and reagent into the little bottle bit by bit until the dot "just diappears"..does that mean until it STARTS to disappear or until it's fully obscurred?

    BTW, WOW...my pool isn't done with this process but it has NEVER looked this good!! Can't wait until it's really ready!

    Thanks again everyone!

  14. Back To Top    #14
    JasonLion's Avatar
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    Every once in a while a Leslie's actually stocks a FAS-DPD test kit, but it is fairly rare. You pretty much need to purchase them over the Internet.

    On the CYA test the black dot should be totally gone.
    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

  15. Back To Top    #15
    i called the Leslies near here. They don't have it but he said what they do if they want to get a near-true reading on something over FC5:

    - cut the volume of water to be test by half with distilled water (dilute the test water)
    - retest

    if the test still read over 5, dilute by half again and test again

    once you have a reading at or near 5, you multiply 5 x the number of dilutions = FC

    so, if my FC is 20, based on his methods:

    my test calls for 9ml of pool water. if I cut that to .5ml of pool water to 8.5ml of distilled water, I should get a FC of 5

    Therefore if my FC is unknown, I start with 4.5ml of pool and 4.5ml of distilled water. If that's over FC5, I would then go to 2.25ml pool water to 6.75ml distlled water and test again. If it is still over 5, move to 1.125ml of pool water and 7.875ml of distilled water and test again...etc

    how reasonable and reliable a process is this...noting that at this point, I have NO way of testing over 5 until I get a "real" test kit?

  16. Back To Top    #16

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    how reasonable and reliable a process is this
    It has always seemed reasonable but, in reality, is seldom reliable for the kind of accuracy you need when getting your water to really sparkle.

    I have tried it a couple of times and not found it to be very close at all. Still, if that's all you've got and it can't be returned, you can "get by".
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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  17. Back To Top    #17
    JasonLion's Avatar
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    In a pinch you can use dilution when you don't have any other choice. But it doesn't begin to compare to having a FAS-DPD chlorine test. The problem with dilution is that the precision goes down significantly. The FAS-DPD test is normally +- 0.5, while an OTO test with a 3 to one dilution is around +- 4 under ideal conditions and often much worse.
    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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