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Thread: Sand or Algae?

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    Sand or Algae?

    Hi,

    Would appreciate some advice.

    Was a new pool owner last year, and completely lost the battle with the water. It started to cloud, I continued to shock, but got nowhere. See previous posts for detail.

    Completely drained pool in the spring, and there was a huge amount of what appeared to be sand at the botom. Had pool cleaned, and filter serviced, and refilled the pool.

    3 weeks in, I notice that there was 'sand' at the bottom of the pool. I vacuumed it, and it was like new.

    4 days later (yesterday) there was a worse covering than before, so I vacuumed again.

    This morning, yet another covering.

    I thought it might be sand but, after reading many posts on here, I wonder if it is the mustard algae. Have attached a nylon stocking (is this what you mean by 'nylon sock'? - we use slightly different terminology over here in the UK, and my wife is convinced that references to nylon sock do in fact mean stocking). I vacuumed initially running through the filter, but it appeared, at least to me, as if the sand/algae was coming straight through the stocking.

    The sand/algae is all over the bottom of the pool, and not just around the outlet, this leads me to believe that it is algae rather than sand. When brushed, it tends to cloud up rather than move.

    Any thoughts on my options from here? Will flocculent help? What about Jolly Jell? I tried the latter last year, without any joy at all. (sorry for the pun!)

    Pool was shocked last year for lengthy periods, to almost industrial levels, hence I am at a complete loss as to where to go from here.

    Any help would be appreciated, thanks in advance.
    1) The size of your pool in gallons 30000
    2) The type filter you have (sand, DE, cartridge) sand
    3) If your pool is an AG (above ground) or IG (in ground) IG
    4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass Tiled
    5) If you know, tell us the size pump and the size (flow rate) of your filter.Size not known but operating at a pressure of around 10psi

  2. Back To Top    #2

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    Re: Sand or Algae?

    Sand is heavy and won't make it very far until it falls to the bottom ending up near the return lines.(If you can pick it up with your fingers it is sand, if you brush it and It disappears in a cloud its algae) mostly people will tell you to keep a very high fc reading to kill the stubborn algae. There are alternatives. Using yellow treat plus will work but it may screw up your chlorine for a while and will basically require you to depend on chlorine feeder with trichloro. Remember yellow algae spores can stick to bathing suits and re-infect your pool after you have this cleared up.
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    JasonLion's Avatar
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    Re: Sand or Algae?

    This doesn't sound like algae to me at all. It sounds more like pollen.

    Floc won't help if it is already settling on the bottom by it's self.

    I would try adding a little DE to the filter.
    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

  4. Back To Top    #4

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    Re: Sand or Algae?

    You can cover the pool to block pollen from entering to determine if it's algae or pollen
    -Kevin
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    22,000 gal / 16' x 32' / Vinyl / Hayward s244t /Pentair SuperFlo 1 hp

  5. Back To Top    #5

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    Re: Sand or Algae?

    EDIT: Sorry, I must have deleted a few important words accidentally....Here is my post as intended:

    Where are you located? This may depend on your locale. In my area (North Florida) pollen is light greenish yellow and tends to float and stay along the scum line. It is also pretty much done falling for the year. Mustard algae, on the other hand develops along the bottom and surfaces like steps and afreas of poor circulation. It is more of a brownish yellow, and gets worse in hot weather. Regular shocking won't clear it up, it takes sustained high levels of CL. If you can find a way to collect some of it in a cup, add bleach and wait a few hours. If it clears or turns white its algae.
    33' above ground pool, 52" deep, about 27500 g
    sand filter w/zeobrite

  6. Back To Top    #6

    Re: Sand or Algae?

    Many thanks for all of the repsonses.

    Pool is covered when not in use (ie most of the time!) with a floating solar cover. There are some gaps, so it would be possible for some pollen to creep in I guess, although the covering seemed pretty even all over the floor of the pool.

    The covering did creep up the side around six inches too, would pollen do this?

    I will capture some in a container, do the bleach test, and advise further.

    Agree that the shocking got nowhere last year. In terms of "sustained high levels of CL", does this refer to FC? How high a level are we looking at, over what period, and what is suggested as the best way of doing this? We use Trichlor tablets in the skimmer, although we do notice that these seem to evaporate very quickly (3 or 4 days). Sorry if I have misunderstood, I am still very much a newbie.


    Thanks again for all of the assistance to date.
    1) The size of your pool in gallons 30000
    2) The type filter you have (sand, DE, cartridge) sand
    3) If your pool is an AG (above ground) or IG (in ground) IG
    4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass Tiled
    5) If you know, tell us the size pump and the size (flow rate) of your filter.Size not known but operating at a pressure of around 10psi

  7. Back To Top    #7

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    Re: Sand or Algae?

    Sorry, my original post was missing some words. I edited it above. As for sustained high levels of FC needed to eliminate mustard algae, this will depend on your CYA level. For me it is at least 15-20 ppm, but I don't have much CYA in my pool. Look at Jason's pool calculator and input your values, it will tell you what you need to shock for mustard, if in fact that is what you have. By sustained, I mean until the algae is gone and the FC level is holding overnight. You will need to brush too, as the algae organisms are encased in a protective layer.

    There are products designed for mustard algae, and perhaps someone more knowledgeable here can recommend one. The ones I have tried either tampered with my test results, introduced unwanted chemicals and/or caused a mammoth CL demand increase. I just figure why spend the money on a product that will cause me to need alot more CL when I can just put in alot more CL in the first place. With mustard, prevention is key. The only time I get it is when I let my CL levels get too low.
    33' above ground pool, 52" deep, about 27500 g
    sand filter w/zeobrite

  8. Back To Top    #8

    Re: Sand or Algae?

    Thanks for the clarification Miranda.

    We are based in the UK (yes - we do get some sun here occasionally!). CYA is not commonly used in the UK, and I have none in my pool.

    I put a container at the bottom of my pool last night, and swept around some of the 'dust' to stir it up. I will do a bleach test this evening.

    I am fairly certain that this is not pollen. It is definitely at the bottom of the pool, and not around the waterline.

    I tested my FC this morning, and it was getting low, so I added some stabilised chlorine granules to the skimmer, and put the pump on before I left for work.

    Must say that the thought of trying to shock this out fills me with dread. Went down this route last year, adding huge quantities of shock, sustaining shock levels for very lengthy periods, and all to no effect. Certainly don't want to be there again, throwing good money and time after bad. Would rather just close the pool and forget about it than go through all that again.

    Thanks for the advice, let me think on it.
    1) The size of your pool in gallons 30000
    2) The type filter you have (sand, DE, cartridge) sand
    3) If your pool is an AG (above ground) or IG (in ground) IG
    4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass Tiled
    5) If you know, tell us the size pump and the size (flow rate) of your filter.Size not known but operating at a pressure of around 10psi

  9. Back To Top    #9
    JasonLion's Avatar
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    Re: Sand or Algae?

    If you have seen it on the walls of the pool, especially on the shady side of the pool, then it could be mustard algae. Mustard algae will go away when you shock and brush the pool, and then tends to come back when the FC level goes down again. Pollen is not affected by shocking at all.
    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

  10. Back To Top    #10
    Barbara C's Avatar
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    Re: Sand or Algae?

    Just a thought, have you tested for CYA?? Trichlor tablets in the the states have it built in. May be possible your shock level needs to be higher than thought and so your regular maintenance FC would need to be higher also.
    24' AG Vinyl
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    Re: Sand or Algae?

    Quote Originally Posted by adadof3
    Thanks for the clarification Miranda.

    We are based in the UK (yes - we do get some sun here occasionally!). CYA is not commonly used in the UK, and I have none in my pool. Oh yes it is! and its in most of the pre packaged products (dichlor, trichlor and shock) also on it's own in granular form.

    Must say that the thought of trying to shock this out fills me with dread. Went down this route last year, adding huge quantities of shock, sustaining shock levels for very lengthy periods, and all to no effect. Certainly don't want to be there again, throwing good money and time after bad. Would rather just close the pool and forget about it than go through all that again.

    Thanks for the advice, let me think on it.
    Yes I remember your swamp from last year, you must have a magnifying glass somewhere sand looks well, like sand everything else doesn't.

  12. Back To Top    #12

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    Re: Sand or Algae?

    Quote Originally Posted by adadof3
    Thanks for the clarification Miranda.

    We are based in the UK (yes - we do get some sun here occasionally!). CYA is not commonly used in the UK, and I have none in my pool.

    I tested my FC this morning, and it was getting low, so I added some stabilised chlorine granules to the skimmer, and put the pump on before I left for work.
    CYA and stabiilizer are basically the same thing. CYA (cyanuric acid) is the chemical that stabilizes it, so you probably DO have CYA in your pool, they just call it something else over there, like "stabiliser". If you have been chlorinating long term using stabilized chlorine tablets or granules, and shocking with powdered shocks, it is very possible that your CYA levels are very high and contributing to your problems. Ask if your pool store tests for stabiliser, or sells a test kit.
    33' above ground pool, 52" deep, about 27500 g
    sand filter w/zeobrite

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    Re: Sand or Algae?

    Quote Originally Posted by Miranda
    Quote Originally Posted by adadof3
    Thanks for the clarification Miranda.

    We are based in the UK (yes - we do get some sun here occasionally!). CYA is not commonly used in the UK, and I have none in my pool. Oh yes it is! and its in most of the pre packaged products (dichlor, trichlor and shock) also on it's own in granular form.


    I tested my FC this morning, and it was getting low, so I added some stabilised chlorine granules to the skimmer, and put the pump on before I left for work.
    CYA and stabiilizer are basically the same thing. CYA (cyanuric acid) is the chemical that stabilizes it, so you probably DO have CYA in your pool, they just call it something else over there, like "stabiliser". If you have been chlorinating long term using stabilized chlorine tablets or granules, and shocking with powdered shocks, it is very possible that your CYA levels are very high and contributing to your problems. Ask if your pool store tests for stabiliser, or sells a test kit.
    And don't accept a test done by dip strip!!! recently I tested 3 pools between 140-190ppm CYA and the three diferent companies dip strips read 20-30 and 0.

    CYA just cannot be accurately measured that way.

  14. Back To Top    #14

    Re: Sand or Algae?

    Many thanks for all of the responses.

    Would have to check the tablets etc to see if there is CYA. If there is, then it is likely to be minimal, as the pool was completely emptied and refilled only a month ago. Am fairly sure that the same questions were asked last year though, and it was concluded that there was no CYA.

    Am certain that this is not sand. It is far too fine to be picked up, it dissolves when brushed, and there is an even distribution all over the pool. It just looked like sand initially, to the untrained eye.

    Shocked the pool last night, only to find that it looked even cloudier this morning. A marginal improvement might have indicated to me that I was moving in the right direction; even no difference might have been undertandable, as it could have been taking time to take effect; but worse? I just don't understand at all. This is exactly how it started last year, and it was all downhill from there.

    Perhaps I am doing something wrong with the shock?

    I am using granules, using twice the dosage suggested on the manufacturer's instructions. I dissolve these granules in water taken directly from the pool, in large plastic containers which I shake vigorously, then leave to stand for a couple of minutes. Half of the solution I pour very slowly in above the outlet from the pump, the rest I pour around the edge of the pool. As I get to the bottom of each container of solution, I redillute with pool water several times, in order to ensure that all granules are fully dissolved. The entire process takes me around two hours, possibly a little more. I then leave the cover off overnight, with the pump running constantly. I covered the pool this morning, as the forecast is for a hot and sunny day.

    Does all of the above look correct? Could there be a problem with the granules that I am using (I assumed this last year and swirched brands, but this had no effect whatsoever).

    Am at a complete loss as to where to go from here, so any advice would be appreciated.


    Thanks in advance.
    1) The size of your pool in gallons 30000
    2) The type filter you have (sand, DE, cartridge) sand
    3) If your pool is an AG (above ground) or IG (in ground) IG
    4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass Tiled
    5) If you know, tell us the size pump and the size (flow rate) of your filter.Size not known but operating at a pressure of around 10psi

  15. Back To Top    #15
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    Re: Sand or Algae?

    I have had a similar problem, but it's only periodic. I had algae-free water, with some very fine debris (dead algae?) that would settle on the floor and also remain it suspension, giving me slightly cloudy water.

    All the advice given so far has been valid, but here is what worked for me:
    Backwash the filter until the backwash water runs clear, run the rinse cycle for 30 to 60 seconds, then return the filter to the filter setting;
    Add a filter helper, such as a bit of DE or a cup or two of Fiber Clear;
    Vacuum and visible "settlings";
    Brush the walls & bottom to get any remaining "stuff" into the pool water;
    Run the pump & filter 24/7 until the water gets sparkling clear, then as many hours per day as it takes to keep it that way (I run mine 24/7 all season long).

    Remember that any filter helper is backwashed out each time you backwash, so you will have to add it again after each backwash.

    This trick worked for me in less than 48 hours. Had to backwash then due to high filter pressure thanks to the trapped debris. Added another dose of Fiber Clear and have had sparkly water ever since.

    Good luck!
    36K gallon 42X22 gunite/plaster kidney-shaped IG;
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  16. Back To Top    #16
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    Re: Sand or Algae?

    Hi Dad,

    You can get the Palintest SP315C kit - which measures cya as well as ta and ch - from Confederate Chemicals in Wales at http://www.poolandspachemicals.co.uk although it is expensive. Palintest also do a separate cya tester (SP620) if you already have the other test stuff which you can get from Palintest themselves, have a look at http://www.palintest.com

    I don't know what part of the UK you are from, but I don't know where you would get pollen in that quantity. It looks like dead algae to me, especially if it's grey, or dirty white. Is the water clear?

    I would never vacuum through the filter, always to waste, then rinse. I also have some slight residue of dead algae in our pool and with a cover it's a pain to vacuum, so when I swim - twice a day in this glorious spell - I kick the stuff up in the hope that some will get sucked into the filter, the equivalent of brushing I guess. You can of course get the water polisher tabs to go into the skimmer if you wish which might help. I assume you are backwashing fairly frequently.

    You mentioned using a container to catch the culprit. Does your pool not have a sump? I'm curious as ours doesn't, and I thought we were unique.
    11,000 Imp galls inground hopper 15' x 35', Delifol liner (vinyl), sand filter, Abrisud Classic cover, Palintest 315C test kit

  17. Back To Top    #17

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    Re: Sand or Algae?

    Adadof3,

    you are using tablets so you are adding CYA, you are using shock at twice the amount so adding CYA at twice the ammount (one of the reasons BBB uses bleach because that doesn't add it)

    Anyway that doesn't help you with the yellow dust. are you cleaning with vacuum to waste set on your multiport valve?

    If the dust is fine and your filter sand is chanelled it is quite possible for this to circulate through the filter and back into the pool.

    As Jason said adding DE powder to your filter may help.

  18. Back To Top    #18

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    Re: Sand or Algae?

    I overlooked the fact that you recently drained and refilled.....that sheds a different light on things. With that in mind, I doubt the CYA is high enough to cause a problem. If you know how much and what type of chlorine you have put into your pool since you filled it, we can roughly calculate how much CYA is in there now. (For example of you have used up a 15 lb bucket of 75% trichlor, or dichlor (look at the ingredients listing) we could figure that out for you.
    33' above ground pool, 52" deep, about 27500 g
    sand filter w/zeobrite

  19. Back To Top    #19

    Re: Sand or Algae?

    Thanks for all of the responses.

    Back in office now, so unfortunately can't give you any info on the tablets that I have been using. Will see if I can get that info tonight, but I really don't think that CYA is an issue.

    For those that have asked location, we are in mid-Essex, out towards the coast. We do have woods within the grounds and beyond, so I did think that pollen might have been the issue; having looked into this a bit further though, I think it pretty clear that it is algae.

    So, what did I do yesterday?

    I got my wife to switch off the pump mid-afternoon, in order to allow any 'dust' to settle. When I got home, I then vacuumed the floor of the pool, with the water going to waste (I only ran it through the filter on Sunday, as I was under the impression that it was filter sand that I was picking up). The water was still cloudy, although it was just about possible to make out the bottom of the pool at the deep end. I then shocked the pool again, with an even higer dose than the previous night. This time I poured some of the diluted shock through the skimmer, although I am not sure if this will make any difference at all.

    Tested the pool this morning, and it was still just over shock level. What was interesting though was that it was more of a milky colour, rather than the green of late. Not sure if this relevant, it may even have been a trick of the light and/or my blurry eyes! I covered the pool, and have left the pump running.

    Does it sound as if I am making progress?

    Not sure whether to get my wife to add more shock during the day, or whether I should go through the vacuum and shock process again this evening. Any thoughts?

    DE does sound interesting. I googled it earlier this week and saw that it was widely available, so was going to get my wife to get some today. Further reading of this site though shows me that there are two types of DE, and that the commonly available one is suitable for gardening rather than pools. May need to order some in.

    Will keep you posted, and thanks again for all of the assistance to date.
    1) The size of your pool in gallons 30000
    2) The type filter you have (sand, DE, cartridge) sand
    3) If your pool is an AG (above ground) or IG (in ground) IG
    4) If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass Tiled
    5) If you know, tell us the size pump and the size (flow rate) of your filter.Size not known but operating at a pressure of around 10psi

  20. Back To Top    #20
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    Re: Sand or Algae?

    Adadof3, I can't see any FC or any other figues in your posts. What fc are you shocking to? Use a simple DPD1 test and dilute the pool water carefully (i.e. mix an accurately measured amount of pool water with say three times the amount of just as accurately measured distilled or chlorine-free water, fill your test kit with that, test, multiply the results by 4).

    We seem to have gone from Sand or Algae to Green to Milky. I can only advise hold at the measured shock level, run the pump 24/7, brush and backwash daily, or twice daily if neccessary. I would not switch off the pump to enable the algae to settle.

    Through my own misunderstanding I had a green attack earlier this year. I had to shock to the low to mid-twenties to clear the water, which it eventually did over four to five days. 'Shocking' to under ten, which I had been doing previously, was a complete waste of time, effort, nerves and money.
    11,000 Imp galls inground hopper 15' x 35', Delifol liner (vinyl), sand filter, Abrisud Classic cover, Palintest 315C test kit

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