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Thread: At what FC level can we swim?

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    At what FC level can we swim?

    I've been shocking my pool since Sunday. I've maintained it up at 15 FC since Sunday morning. Today was overcast, and I lost very little FC. Measured first thing in the morning (6am), added some bleach to get up to 15. Measured at about 3pm, I was still at 14 FC. Kicked it back up to 15, and when I just went to measure (9pm), I was still at 15 FC. So, I didn't add any more bleach, and I'll measure first thing tomorrow morning, but I'm guessing that it will hold and I'll be done with the shock.

    So, when can I allow my kiddos to get in? My daughter has been begging me since April (yes, she'll get in when the pool is about 65 degrees if I let her!). A FC of 15 seems pretty dang high. I had barely any CYA, so I've added 2 pounds over the last day (in a sock in the skimmer basket) with a goal of getting it up around 35 or this time around. I'm thinking that I'll want to maintain the FC at 5 normally, but that I can let my daughter get in before then, though I'm not sure how much before. Would you get in at 10 FC? 12 FC?

    Thanks!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  2. Back To Top    #2
    searayboater's Avatar
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    Re: At what FC level can we swim?

    Public pools are sometimes kept at 10ppm and no one knows or even cares.
    18' AG Pool, 6900 gallons, 55 sq. ft. Hayward Easy Clear Cartridge Filter, 1hp Power Flow LX Pump, North Texas

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    Guest

    Re: At what FC level can we swim?

    I would wait until it drops below 10 ppm. This will also allow a bit more of the CYA you added to dissolve.

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    Re: At what FC level can we swim?

    I've got a morning update and a question for you all. I measured early this morning (5:30), and got 14. So, I lost 1 FC overnight. My water is NOT crystal clear, though. It is fairly clear - as in, I can see the design on the bottom, but it's only a 3 ft deep pool - but I can tell there is still some cloudiness. Should I just maintain at 15 for a bit longer? I went ahead and kicked it back up to 15 this morning, and I'm thinking maybe I need to maintain that for a while longer?
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

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    JasonLion's Avatar
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    Re: At what FC level can we swim?

    I would maintain shock level for another day, even though it might not be required. It is good to be completely sure you have gotten rid of the algae.

    Also, remember to keep an eye on the filter pressure and clean/backwash the filter as needed.
    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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    duraleigh's Avatar
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    Re: At what FC level can we swim?

    You are doing a great job of testing and dosing your FC accurately. I agree with Jason to hold for another day just to make sure. Smaller pools filters are infamous for not having much capacity and I suspect your filter is simply a little behind in the cleanup process. Check your guage to make sure you don't need to backwash.

    I have swum in water @25ppm with no problems and would do so again.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: At what FC level can we swim?

    Op here again. So, I was at work and unable to get back to the pool until 5pm today. From 5:30am to 5:00pm it went from 15 to 12. Is that more significant than you would have thought if there was no organic gunk in it, or is that about right? It's been overcast today, windy, with lots of these weird little seed things dropping into the pool from an overhanging shrub "wall" and some rain, if that makes a difference.

    The water actually looks noticeably clearer than it did this morning, which I'm taking as a very good sign.

    I DO think I need to backwash the filter. However, I just added the CYA on Mon, and I thought I read that I should wait a week to backwash?

    Thanks for all the help I'm getting!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

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    frustratedpoolmom's Avatar
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    Re: At what FC level can we swim?

    That's a VERY good loss, I would have expected more, actually.

    How did you add the CYA, what application method?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: At what FC level can we swim?

    I put the CYA granules into a leg of old panyhose, tied it off, and put it in the filter basket. I sort of draped it over the handle, so it wouldn't block the water too much. I did two applications, about 1 lb. each time. I was surprised at how quickly the CYA was gone out of it - pretty much overnight.

    So, you think with a loss like that, and my 1 FC loss last night, it's safe to assume that I've shocked the pool satisfactorily? I'm going to keep it at 15 for today, I'll do one more add tonight before bed, but then I'd really like to let the FC go down a bit so the kids can actually get in the dang thing! And I really, really don't want to have to get up at 5:30am again tomorrow if it's not warranted!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  10. Back To Top    #10
    frustratedpoolmom's Avatar
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    Re: At what FC level can we swim?

    Quote Originally Posted by thewritegirl
    I put the CYA granules into a leg of old panyhose, tied it off, and put it in the filter basket. I sort of draped it over the handle, so it wouldn't block the water too much. I did two applications, about 1 lb. each time. I was surprised at how quickly the CYA was gone out of it - pretty much overnight.

    So, you think with a loss like that, and my 1 FC loss last night, it's safe to assume that I've shocked the pool satisfactorily? I'm going to keep it at 15 for today, I'll do one more add tonight before bed, but then I'd really like to let the FC go down a bit so the kids can actually get in the dang thing! And I really, really don't want to have to get up at 5:30am again tomorrow if it's not warranted!
    Keep the filter running tonight, add the bleach as you planned, you should be able to backwash tomorrow just fine, and allow the FC to drop to normal levels. Usually FC drops during the day are a percentage, and when the FC is that high, it will usually drop by like 50%, so your loss was minimal...was the pool covered? At any rate, I think you will see a new pool tomorrow. Just be patient. Even after algae is all dead, sand filters can take longer to clear up cloudiness associated with algae blooms.

    We tell people not to backwash the filter, usually because they added the CYA directly to the filter, instead of the sock. Since you did the sock, you should be okay, especially after 3 full days. Go for it!

    I think they'll be swimming this weekend......Friday even? I'll keep my fingers crossed.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  11. Back To Top    #11

    Re: At what FC level can we swim?

    Yay! I'm looking forward to it!

    The pool was not covered - however, it's been really overcast and cloudy here so there was very little direct sun today. The pool is also narrow, and between the house and a fence, so it doesn't get nearly a full day of sun anyhow. Maybe that has something to do with the less than normal loss? Kinda funny, because the previous few weekends it's been beautiful and 90+ degrees here, but the pool looked...uninviting. Now, the pool looks good and it's raining! Of course, right?!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

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    frustratedpoolmom's Avatar
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    Re: At what FC level can we swim?

    Of course.

    Yes, that would explain the minimal loss. That's good. It means BBB will be REALLY cheap for you.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: At what FC level can we swim?

    Another update and more questions. My levels today look really good. This afternoon:

    FC - 8
    CC - 0
    TA - 90
    Ph - 7.4 (*i think* I have a really hard time with the colors on this one).
    I haven't rechecked the CYA yet, because I added some Mon and don't have a ton of the testing reagent left, so I thought I'd wait till Mon to test again. I'm operating on the assumption that I'll be around 35-40 by then.

    I backflushed yesterday afternoon, but only for a minute or so. That's usually my dh's job, and I wasn't sure how long to do it for. The water that I could see looked fairly clear, though. The pool looks pretty nice, the water is pretty clear. However, it's not "sparkling," and I'm wondering how to fix it. I have this wall of shrubs that drops these weird little round seed/berry things CONSTANTLY. They are smaller than a marble - like a garbonzo bean. There is one corner of the pool that all the leaves/droppings pile up in, like I'm not getting good circulation through there. I have two returns, one on each 12' end of the pool, and the skimmer is on one of the long sides. I tried to adjust the returns, but they barely adjust, unless I'm doing something wrong. They will go just a few degrees from "straight ahead."

    Thoughts on getting my water truly sparkling? I will try to post a pic in just a second here and see if that helps. Thanks again for all of your input!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  14. Back To Top    #14
    frustratedpoolmom's Avatar
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    Re: At what FC level can we swim?

    How often are you running your filter/pump?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  15. Back To Top    #15

    Re: At what FC level can we swim?



    I'm sorry this isn't a great picture - it's from my phone, and the cloudy yet bright day just makes everything seem a little weird. Anyhow, see the ducky in the corner? That's where all the leaves and green matter wind up, if the skimmer doesn't get them or I don't get them before they sink to the bottom. You can see shadow of all the crazy shrubs in the pool! Grr! They need to be trimmed WAY back, but we didn't do it, and now I don't want to do it, because it will dump a ton of stuff into the pool. :P In a few weeks, I think they stop dropping all the weird berries, though, if I remember correctly.

    Also, you can see what I mean about this being a very narrow space. The pool takes up the entire space between the area that's below a deck and the fence to our neighbor's house. There is a very narrow concrete walkway on the one side, and only slightly wider on the other.

    And yes, the float is empty! :P My kids like it for some reason.
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  16. Back To Top    #16

    Re: At what FC level can we swim?

    Running the filter 24/7.
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  17. Back To Top    #17
    frustratedpoolmom's Avatar
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    Re: At what FC level can we swim?

    Oh. Hmmm.

    Well, honestly sand filters just take a while to clear. It can take a week for it to fully clear up after algae. You could try skimmer socks or the DE in the filter trick. Instructions are in Pool School.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  18. Back To Top    #18

    Re: At what FC level can we swim?

    Ok. I'm going to get a "real" skimmer sock today, so we'll see if that helps me get some "sparkle" over the weekend! I'll look up the DE on Pool School, not familiar with that.

    Just as a side note, though, the kids GOT IN today!!!! It was flippin' freezing cold water (right about 71), and they only lasted a few minutes, but dang it, it's swimmable!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

  19. Back To Top    #19

    Re: At what FC level can we swim?

    Thought I'd add one more update about the pool. I was having trouble with the flow of water, and I was trying to point the returns so they would make the water sort of go around in a counter-clockwise position, but I was getting that one corner that had build-up. So, instead, I tried pointing the returns straight ahead. I also put a filter sock (not a "real" one, as wal-mart didn't have them, but just a knee-high nylon) on the filter. In a day, the rest of the cloudiness had gone completely away. It could have been one of these two things, or just the fact that my filter took a full week to really clear the water, but whatever it was, it worked. My water looks great!
    12x40x3 IG lap pool, vinyl liner. 26" sand filter, 1HP pump.

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