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Thread: lost fight with algae?

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    lost fight with algae?

    hi,

    I have been following advice on this forum for a year or so. Thank you all for great help.

    Most of the summer (southern hemisphere) I have been fighting green algae. I did shock the pool at least 5 times this season which is I think quite a lot. Each time I had almost no CC but had to keep shock levels for about a week to clean the water. Usually 2-3 weeks after treatment the pool got algae back. If I don't have the cleaner running (suction cleaner) I get green stuff on the walls and stairs which after brushing makes the pool cloudy. With the cleaner running the water just turns milky.

    The thing is I have the water balanced all the time. PH is ok, FC usually too high even (I don't think it ever dropped below 5 this summer). The filter runs for 8h a day. The pool wasn't suitable to use more time that it was this season and I don't know how to get rid of algae permanently. Where does it come from?
    how often do you shock your pools in season?

    cheers
    Pawel
    16000 gallons, SWG, IG/concrete, sand filter, the pool is 20+ years old probably

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    Re: lost fight with algae?

    Sounds like your FC is not high enough to be effective. Your CYA may be too high. Can you post full test results? How are you add chlorine to the pool? I haven't shocked my pool since last August. I read a post yesterday about some folks go years without shocking.
    20' x 38' x 40' Lagoon, 38K Gal, Vinyl, Aqua Plus control, SuperFlow 2 hp pump, 3.7 sqft sand filter, T-15 SWG
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    BoDarville's Avatar
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    Re: lost fight with algae?

    p0las:

    Sorry to hear about your ongoing algae fight.

    Can you post some test results? This will allow us to help you more effectively. The first thing that comes to mind is your CYA level. Without knowing what that is, you cannot properly shock the pool. The CYA will determine the maintenance FC range as well as the FC level needed to properly shock the pool. A FC of 5 may not be high at all depending on your CYA. In fact, it could be too low for your CYA and that could be causing the algae to come back.

    BTW, shocking is a process and not a product. If you haven't already read this article, I would recommend doing so: http://www.troublefreepool.com/pool-...king_your_pool This process needs to be followed to the letter in order to properly shock. It may require testing FC level more than once a day. Depending on the severity of the algae outbreak, it could take a while to complete the process.

    Other items to be aware of include any nooks and crannies such as ladders, eyeballs, areas around light fixtures, or any other areas of the pool that may be subject to low circulation where resistant algae could survive. These areas need to be brushed so that the algae will be fully exposed to the chlorine and killed off. Also, any pool toys should be disinfected otherwise they could reintroduce any surviving algae back into the pool.

    As for how often a pool is shocked, that depends. There are several of us on the forum that haven't shocked their pools in years (I'm going on two years). This does require routine testing and keeping water chemistry balance within recommended guidelines. The shock process should be done only when needed and not according to an arbitrary timetable as many manufacturers of "shock" products would have you believe.
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    Re: lost fight with algae?

    Hi.
    I shock using the procedure described in the pool school.
    CYA at the moment is at 40 but was at 50 before when I did most of the shocking.
    TA 150.
    FC always above 5. When shocked was high like 17-19.
    CC 0
    PH 7.8
    CH 220

    I dissolve granular chlorine in a bucket and pour around the pool. Normally SWC is keepin chlorine level. I test weekly. Daily when shocking.

    I have lots of trees so there are leaves constantly falling into the water and there is most likely high level of phosphorites in the pool but this shouldn't matter if FC keep algae at bay. Which it clearly doesn't. I checked and brushed all the gaps between tiles this spring to make sure there is nothing there, no ladder or other places for algae to hide...

    Pawel.
    16000 gallons, SWG, IG/concrete, sand filter, the pool is 20+ years old probably

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    linen's Avatar
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    Re: lost fight with algae?

    What is the "granular chlorine"? Trichlor, calhypo?
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: lost fight with algae?

    Quote Originally Posted by linen
    What is the "granular chlorine"? Trichlor, calhypo?
    Calcium hypochlorite (65%). I use it only to shock the pool.
    16000 gallons, SWG, IG/concrete, sand filter, the pool is 20+ years old probably

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    elwood58's Avatar
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    Re: lost fight with algae?

    Quote Originally Posted by p0las
    Quote Originally Posted by linen
    What is the "granular chlorine"? Trichlor, calhypo?
    Calcium hypochlorite (65%). I use it only to shock the pool.
    Good choice so long as your CH is under control.
    19204 Gallon L Shape with a 10X10 2nd Step Baja Ledge. Intellichlor IC-40, IntellipH, Cartridge Filter, Pentair Heater/Chiller (Heat Pump). Tons of Deck with Deck Jets. Construction Complete 6/5/17.

    "If you don't measure it, you can't manage it!"

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    Re: lost fight with algae?

    Your pool is 20+ years old. Is the plaster that old as well and is it rough? How is the circulation in your pool? It may be that rough areas in the plaster and poor circulation are allowing algae to grow where chlorine is not circulated well. This is why the algae is green on the surfaces but turns white/cloudy if you brush the algae since it then gets exposed to chlorine which bleaches it out. Even so, this isn't a common situation. As others have noted, 5 ppm FC is not necessarily high since that is the minimum FC for a CYA of 70 while higher CYA levels would need a higher FC.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: lost fight with algae?

    Quote Originally Posted by chem geek
    Your pool is 20+ years old. Is the plaster that old as well and is it rough? How is the circulation in your pool? It may be that rough areas in the plaster and poor circulation are allowing algae to grow where chlorine is not circulated well. This is why the algae is green on the surfaces but turns white/cloudy if you brush the algae since it then gets exposed to chlorine which bleaches it out. Even so, this isn't a common situation. As others have noted, 5 ppm FC is not necessarily high since that is the minimum FC for a CYA of 70 while higher CYA levels would need a higher FC.
    hmm I was told that FC higher than 5 is dangerous for the equipment, clothing etc.

    according to CYA chart (pool school) 5 is plenty for SWG

    Code:
    CYA (Stabilizer)	Minimum FC	Target FC	Shock FC
    60 3 4 24
    70 3 5 28
    80 4 6 30
    is regular brushing of the walls a common maintenance? It seems I should do it once a week in the season.
    16000 gallons, SWG, IG/concrete, sand filter, the pool is 20+ years old probably

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    duraleigh's Avatar
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    Re: lost fight with algae?

    hmm I was told that FC higher than 5 is dangerous for the equipment, clothing etc.
    It's not.....assuming you have the appropriate CYA level.


    is regular brushing of the walls a common maintenance? It seems I should do it once a week in the season.
    Of course. Probably a bit MORE important on an older pool to get out any organics that want to hide in the tiny crevices.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    BoDarville's Avatar
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    Re: lost fight with algae?

    Quote Originally Posted by p0las
    PH 7.8
    One other tip is, the next time you need to go through the shock process try lowering your pH to around 7.2 before you begin the shock process. This will make the chlorine more aggressive as a sanitizer. However, once you begin the shock process, ignore the pH - don't even bother testing it. The higher FC levels present during the shock process can skew your pH and if you tested during that process you might over compensate on adjusting the pH. After completing the shock process and after FC levels drop to the normal maintenance level for your CYA, then you can retest pH and adjust if needed.

    And yes, brushing is a necessary task. Not my favorite either but it must be done, especially when fighting algae.
    Gold Supporter, TFP Lifetime Supporter, 26,680 gal Plaster IGP 3.5 - 10' depth / Attached Waterfall Spa, Manually Chlorinated, Triton Sand Filter, 1.5 HP * 1.1 SF = 1.65 SFHP 1-speed Pentair WhisperFlo WF-26 Pump, 400K BTU NG Teledyne Laars Series One Heater, Polaris 360, Test Kit Comparison, Chlorine/CYA Chart, SLAMing Your Pool, OCLT
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