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Thread: Returning Sediment on Liner

  1. Back To Top    #1

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    Returning Sediment on Liner

    If I brush my liner everyday, I get light clouds and the water gets a touch less crystal clear, but returns to normal within the day. The longer I wait the more you can see stuff on the bottom and the more dark mustard yellow the clouds are and the longer it takes to get clear.

    My CYA doesn't register on the TF kit. It is a touch cloudy, but I can still see the dot with the tube filled. At an FC of 16 (pretty high for such low CYA), I lose 1-2 PPM of FC per 24hr period with 4hrs sun, 4 hrs part sun and almost 6hrs of indirect sun.

    My FC was at 16 because it was over 20 and it comes down slowly.

    I just ordered eyeballs for the returns, hoping that redirecting water would help with circulation and help the problem.

    Can't test pH with that high of FC, but it is mid 7 when the Cl is lower.

    TA has been 60-80 in the last month.

    I have a small leak and replenish the water and Cl more often than the CYA.

    I have not done an official OFCLT, but I thought my 24hr loss tests were pretty ok.

    I have kept my FC in the high 20's with just as low of CYA earlier this summer for a week, but the problem always returns.

    According to my neighbors, my pool was abandoned for over 10 years with no cover for a great deal of that time. I have replaced the sand and cleaned the filter since then. That was two years ago and I have repeated achieved crystal clear water with a slow sand filter, meaning that if I keep the FC high until the water is clear, it is at a higher level for longer than a more efficient filter would be. I have earthy colored (light brown/yellow/tan?) stains that have never cleared on the floor in the low end with high FC levels, but I have unintentionally bleached the decorative border just below water level along the sides.

    I have very little FC loss in a hot/bright 24hr period, but I will do an overnight test if 1ppm in a day (24hrs) isn't good enough.

    This is my first pool and my algae blooms always start on the liner and then the water becomes cloudy. Is that the norm or does the water get cloudy and not the liner in a "normal" pool. I am really thinking that the extended neglect have created a permanent algae colony that will take such an extended period of high FC that my liner won't be able to handle it. I say this because my liner is already very noticeable lighter below the water line and I have kept mustard shock level for over a week with little to no FC loss.

    Just keep brushing to keep the liner and water clear and stop complaining? Any thoughts?
    20' x 40' / 33,000 gallon / IG / Vinyl
    200lb sand filter / 1hp pump
    4hrs full sun with about 45 min part sun before and after

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    Re: Returning Sediment on Liner

    The "dust" you are describing sounds like dead algae. If so, you are letting your FC get too low.

    1. How low do you let your FC get before you replenish it?

    2. How much do you add when you replenish it?

    3. Why is your CYA so low?

    4. Can you post a complete set of test results now?

    Include pH even if it is not correct because of high FC.

    pH - ?
    TA - ?
    CH - ?
    CYA - ?
    FC - ?
    CC - ?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

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    Re: Returning Sediment on Liner

    1. How low do you let your FC get before you replenish it?
    Lowest has been 5 with CYA of 30 or less

    2. How much do you add when you replenish it?
    When I am in maintenance mode, I try not to let it get down to the lowest suggested by Pool Calc, maybe 3ppm bump at a time?
    When I am shocking I add as much as I need. I never let it get low. It more often high than it is normal


    3. Why is your CYA so low?
    CYA is low because I have to refill due to a leak I can't find. Rain/Tap water have been the sources of water. I lose very little FC per 24hr period (1ppm per 24hr day, not bad, right?), even at higher FC levels, so it was not a major concern. I would think that I am doing more damage to my pool surfaces with higher FC and lower CYA than I am creating a algae breeding ground.

    4. Can you post a complete set of test results now?

    Include pH even if it is not correct because of high FC.

    pH - 7.8
    TA - 80
    CH - Have not done this, necessary for algae? Only test I don't do... just because
    CYA - cloudy, but not cloudy enough to obscure the dot at the bottom of the test tube after filling the tube
    FC - 7
    CC - 0


    I have had this daily accumulation for weeks despite being in double digit FC numbers. Except when the water is turning green, twice due to absence and inability to run pump due to tree damage (has been fixed for weeks now).

    The longer I don't brush (more than 1 day) the more accumulation on the bottom. It is an almost brown color and creates spicy mustard colored clouds when brushed.

    If I brush daily, there are always clouds from the brushing, but the water stays clear. If I wait 2+ days, water gets cloudy but still shows no CC.

    At shock level, there is daily growth.

    I am unfamiliar with owning a pool before purchasing this house 2yrs ago. When most pools have algae blooms, does there water turn green first or does growth start on the bottom first? My pool gets the growth quickly (few days) and then turns the water cloudy. Is that what normally happens or does the water turn cloudy first?

    With being abandoned so long (10+yrs) , I wonder if there is VERY stubborn growth deep in the liner or lines that would take weeks/months of shock level to get to?

    TFP is straight forward, shock level until no FC loss overnight and clear pool. I SWEAR I have done that plus 3-4 days (1.5-2 weeks easily) thinking that I was doing something wrong.
    20' x 40' / 33,000 gallon / IG / Vinyl
    200lb sand filter / 1hp pump
    4hrs full sun with about 45 min part sun before and after

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    Re: Returning Sediment on Liner

    The OCLT is a darn near foolproof test to rule out algae. Once you pass it's time to look elsewhere to solve the problem. Rarely does it fail to identify an organic problem.

    Let's say you've ruled out algae by passing the OCLT. Next on the list would be the ordinary process of dirt or pollen being blown in the pool. Another thing could be channeled sand which allows dirt to be blown through the sand bed back into the pool. A broken lateral in the filter would do the same.

    Before delving into a filter issue I would get some skimmer socks. Hooking up a fine mesh sock or bag on the return could tell you if anything is being blown through the sand bed. High Calcium can lead to channels in the sand bed. What's your CH reading?

    Sometimes adding a little DE to the filter before vacuuming followed by a good long backwash and rinse mitigates the problem.
    Bill
    18'X4' 7600 Gal AG
    3/4 HP Pentair Pump
    Hayward S166T 100 lb sand filter

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    Re: Returning Sediment on Liner

    Well, even though your description sounds EXACTLY like algae, algae simply cannot exist in the conditions you are describing so I am at a loss as to how to proceed. Your cannot have some super strain of algae nor is your water any different than anyone else's.

    So, the only conclusion I can arrive at is that you do not have algae.....even though your description sounds exactly like algae.

    Your CYA content is a complete mystery as well. You cannot have a pool with basically no CYA and have only 1ppm chlorine loss daily.....it doesn't work like that.....even if you have no algae you do not have adequate CYA to prevent much greater chlorine loss.

    I can only suggest that you have to think of something else that is getting into your pool besides algae but I don't know what it might be.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Returning Sediment on Liner

    My swimmer load is very low to non-existent which helps the chlorine hang around longer. Last year I had very little FC loss also and had very little CYA which allowed me to run a lower daily FC level (say 3- 4ppm), but it was explained to me that having the CYA up a bit and subsequently raising my FC to ideal range (say 5-8ppm) gives me more wiggle room for a high bather load or small algae outbreaks.

    CH=120
    FC=6.5 (drop of 0.5 from 11-2 which is when I get full sun with less than 30 ppm CYA)

    I run 1 cup of DE at all times, but I will increase that amount and see how it goes. I have filter socks but never used, I will install them also.

    Thanks for your time.
    20' x 40' / 33,000 gallon / IG / Vinyl
    200lb sand filter / 1hp pump
    4hrs full sun with about 45 min part sun before and after

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    Re: Returning Sediment on Liner

    At 2 o'clock yesterday, my FC was 6.5. I added 1 of the 1.42 gallon 6% jugs of bleach at 4 o'clock yesterday which should have raised my FC by 2.5-2.9 per pool calculator and experience. I brushed the pool at 9 last night, but only have indirect lighting from a flood light so I couldn't be sure of cloudiness from brushing. As of 10:00 this morning, I had 9-9.5 FC still with the low CYA. I also brushed again at 10:00 this morning and there were greenish clouds on the pool bottom.

    I did vacuum yesterday and my pressure got too high in the middle of vacuuming, I mistakenly shut the filter off and restarted it which allowed things to shift around and I was not trapping the "sediment" as effectively after that. During my next vacuuming, I will backwash and add DE again during the vacuuming process if needed instead of just shutting it off and restarting the filter.

    I currently have a filter sock on and I added DE to the filter. My pressure is at 18psi which is approximately 6psi higher that what I run after backwashing and before DE, so I should be trapping finer particles from a freshly backwashed low of 12psi.

    I added 2 more containers of bleach because we are expecting a good amount of rain through tomorrow morning and I won't be able to check. I should be at an FC level of 15 putting me pretty close to mustard algae shock level.

    I'm frustrated and hoping to hear more info. Will my lower CH of 120 affect anything? I am going to keep vacuuming with the DE and hope it is just sediment that I can't get up. I also am waiting on some eyeballs for my returns that I will direct towards the floor hoping to improve circulation.
    20' x 40' / 33,000 gallon / IG / Vinyl
    200lb sand filter / 1hp pump
    4hrs full sun with about 45 min part sun before and after

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    Re: Returning Sediment on Liner

    I'm frustrated and hoping to hear more info.
    Nothing really to add. The CH reading is just fine.

    Again, algae cannot exist in the conditions you describe....even though it still sounds like algae. It must be sediment of some sort. perhaps the filter socks will help but I don't see how.

    Secondly, you cannot maintain FC in a pool with 0 CYA like you are doing but, yet, you are doing it.

    I am unable to add anything further to your dilemma.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    UnderWaterVanya's Avatar
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    Re: Returning Sediment on Liner

    How old are your reagents?
    Is it possible you are doing the CYA test wrong?
    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: Returning Sediment on Liner

    Quote Originally Posted by duraleigh
    I'm frustrated and hoping to hear more info.
    Nothing really to add. The CH reading is just fine.

    Again, algae cannot exist in the conditions you describe....even though it still sounds like algae. It must be sediment of some sort. perhaps the filter socks will help but I don't see how.

    Secondly, you cannot maintain FC in a pool with 0 CYA like you are doing but, yet, you are doing it.

    I am unable to add anything further to your dilemma.
    I have recently begun to have to same problem - sort of.

    My numbers are all good and have been stable all year.

    CYA = 40
    CH = 230
    TA = 130
    Ph = 7.5

    CL never drops below 4.5. Most of the time it is in 5.5 ppm range
    CC has been 0 for the last 2 months

    I passed the OCLT at the beginning of the season, and have never failed it since (I do it at random just for the heck of it)

    My pool looses 1.0 to 1.5 ppm of CL per day depending on sun and bather load (OK, if there are a LOT of people in it on a sunny day, it can hit 2.0). This consumption has not changed all season.

    For the entire beginning of the season, I would vaccuum or run the Whaoo twice a week or so.

    Lately I have been geting "Stuff" on the bottom of the pool every day. A very fine grayish brown "dust" that collects in the pits and creases in the liner. It plumes up when you brush it, and it is a bear to vaccuum or run the cleaner because it is so fine. It also seems to deposit more the further away you get from the return (hence where the water slows down)

    I know from my pool chemistry it can't be algae. My conclusion - pollen. Pollen counts have been high for the last few weeks around here and we have had some windy days. It is the only thing I can think of. Not much I can do except brush and vaccuum more than usual. Maybe that is the OP's problem as well.


    -dave
    27' Round ABG (17,000 gal) - +/- 11 hours of full sun per day
    Hard plumbed Hayward Perflex EC-40 DE filter w/ 1 HP pump (Got a new one June 2015)
    Filered 4 hours per day (on a timer)
    Pentair Aqualuminator - now working - and now dead once again, this time for good.
    Zodiac Wahoo

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    Re: Returning Sediment on Liner

    Quote Originally Posted by phonedave
    Quote Originally Posted by duraleigh
    I'm frustrated and hoping to hear more info.
    Nothing really to add. The CH reading is just fine.

    Again, algae cannot exist in the conditions you describe....even though it still sounds like algae. It must be sediment of some sort. perhaps the filter socks will help but I don't see how.

    Secondly, you cannot maintain FC in a pool with 0 CYA like you are doing but, yet, you are doing it.

    I am unable to add anything further to your dilemma.
    I have recently begun to have to same problem - sort of.

    My numbers are all good and have been stable all year.

    CYA = 40
    CH = 230
    TA = 130
    Ph = 7.5

    CL never drops below 4.5. Most of the time it is in 5.5 ppm range
    CC has been 0 for the last 2 months

    I passed the OCLT at the beginning of the season, and have never failed it since (I do it at random just for the heck of it)

    My pool looses 1.0 to 1.5 ppm of CL per day depending on sun and bather load (OK, if there are a LOT of people in it on a sunny day, it can hit 2.0). This consumption has not changed all season.

    For the entire beginning of the season, I would vaccuum or run the Whaoo twice a week or so.

    Lately I have been geting "Stuff" on the bottom of the pool every day. A very fine grayish brown "dust" that collects in the pits and creases in the liner. It plumes up when you brush it, and it is a bear to vaccuum or run the cleaner because it is so fine. It also seems to deposit more the further away you get from the return (hence where the water slows down)

    I know from my pool chemistry it can't be algae. My conclusion - pollen. Pollen counts have been high for the last few weeks around here and we have had some windy days. It is the only thing I can think of. Not much I can do except brush and vaccuum more than usual. Maybe that is the OP's problem as well.


    -dave
    I'm not the expert - but when I read this post:
    chlorine-cya-chart-t2346.html#p18157

    It seems to me you could easily have a low-level mustard algae outbreak that is held mostly in check but not eliminated. The minimum for MA is 6.1 at a CYA of 40; but the shock level is 23.8! You can keep it at bay when you are > 6.1, but not eliminate it. It might be so low level it's below the 1ppm OCLT.

    But again - I'm just guessing here based on what I am reading from folks like Chem Geek.
    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: Returning Sediment on Liner

    It seems to me you could easily have a low-level mustard algae outbreak that is held mostly in check but not eliminated. The minimum for MA is 6.1 at a CYA of 40; but the shock level is 23.8! You can keep it at bay when you are > 6.1, but not eliminate it. It might be so low level it's below the 1ppm OCLT.
    OP reports CYA level of near zero.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Returning Sediment on Liner

    Quote Originally Posted by duraleigh
    It seems to me you could easily have a low-level mustard algae outbreak that is held mostly in check but not eliminated. The minimum for MA is 6.1 at a CYA of 40; but the shock level is 23.8! You can keep it at bay when you are > 6.1, but not eliminate it. It might be so low level it's below the 1ppm OCLT.
    OP reports CYA level of near zero.
    True - the response was to Phonedave who was mentioned his "similar" situation.
    His CYA reported was 40.
    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

  14. Back To Top    #14

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    Re: Returning Sediment on Liner

    Quote Originally Posted by UnderWaterVanya
    I'm not the expert - but when I read this post:
    chlorine-cya-chart-t2346.html#p18157

    It seems to me you could easily have a low-level mustard algae outbreak that is held mostly in check but not eliminated. The minimum for MA is 6.1 at a CYA of 40; but the shock level is 23.8! You can keep it at bay when you are > 6.1, but not eliminate it. It might be so low level it's below the 1ppm OCLT.

    But again - I'm just guessing here based on what I am reading from folks like Chem Geek.
    I have been using this chart

    pool-school/chlorine_cya_chart_shock

    Which shows a minimum FC of 3.0 and a target of 5.0

    I have a vacation comming up. I'll run the Cl up to double digits before I go and add the floater with some pucks (I hate doing that, but with nobody to take care of the pool, it's the only way I have to get CL into it when I am away) and see what that does.



    -dave
    27' Round ABG (17,000 gal) - +/- 11 hours of full sun per day
    Hard plumbed Hayward Perflex EC-40 DE filter w/ 1 HP pump (Got a new one June 2015)
    Filered 4 hours per day (on a timer)
    Pentair Aqualuminator - now working - and now dead once again, this time for good.
    Zodiac Wahoo

  15. Back To Top    #15

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    Re: Returning Sediment on Liner

    Water does react to the CYA test, it just does not get cloudy enough to block the dot at the bottom of the TF test kit. It is less than 30, just don't know how much less.

    I raised my FC to mustard algae shock level wondering the same thing this morning. Whatever I have, starts on the liner, not in the water, I am still not sure if that is common for algae outbreaks, if that is a sign of a specific algae, i.e. mustard algae, or if there is no such thing as normal with an algae outbreak. My water starts very clear with the build up starting on the liner.

    This is a re-occurring problem over the last two summers. Algae outbreak, I raise FC and have beautiful, crystal-clear water and drop down to recommended levels and the outbreak returns.

    I also mentioned that the liner is old and the pool was left abandoned and cover-less for 10 years per the neighbors. The pool was a swamp with layers upon layers of leaves and sediment on the bottom. It took weeks of work and trailers full of debris to clean it up. Is it possible that the algae is entrenched in the liner deeper than average due to the length of being allowed to go unchecked and regular shock procedures and tests kills the surface of the algae, but not down to the "root". Once FC levels go down a bit, the "root" is able to regrow.

    I had that thought early this summer and ran for a week at mustard algae shock level, but the problem consistently returns.

    It is an old liner and there is a slow leak somewhere, so there are plans to replace liner and lines and start fresh for many reasons, just not this summer.

    So...
    1. Is there a standard series of events for an algae outbreak?
    -Cloudy water, then algae on liner
    -Algae on liner, then cloudy water
    -No, get on with your life

    2. Does an abandoned pool have a different "level" or "depth" of algae than a pool that was let go for a week or, again, "No, get on with your life"?

    3. My pH was at 7.8, should I lower it to help with possibly treating mustard algae?
    20' x 40' / 33,000 gallon / IG / Vinyl
    200lb sand filter / 1hp pump
    4hrs full sun with about 45 min part sun before and after

  16. Back To Top    #16
    UnderWaterVanya's Avatar
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    Re: Returning Sediment on Liner

    Quote Originally Posted by phonedave
    Quote Originally Posted by UnderWaterVanya
    I'm not the expert - but when I read this post:
    chlorine-cya-chart-t2346.html#p18157

    It seems to me you could easily have a low-level mustard algae outbreak that is held mostly in check but not eliminated. The minimum for MA is 6.1 at a CYA of 40; but the shock level is 23.8! You can keep it at bay when you are > 6.1, but not eliminate it. It might be so low level it's below the 1ppm OCLT.

    But again - I'm just guessing here based on what I am reading from folks like Chem Geek.
    I have been using this chart

    pool-school/chlorine_cya_chart_shock

    Which shows a minimum FC of 3.0 and a target of 5.0
    The standard chart is for standard problems. The Mustard Algae specific info is contained in that post. No idea if that's the problem - but it could explain why you are "holding your own" but not getting rid of the problem.

    Or it could be confusion on my part.
    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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