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Thread: Possible Algae?

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    Possible Algae?

    We currently have crystal clear water but have needed to increase the output on our SWG to keep the FC above the minimum per the FC/CYA chart. The pool water is in the range of 84-86 degrees and is in full sun for about 60% of the day. I don't remember having the SWG at 50% or more last year (1st season with pool) to keep the FC above minimum. I noticed that the floor was slippery this weekend prior to cleaning and brushing. Could I be on the verge of an algae outbreak? We will do an overnight FC test tonight and post a complete set of results tomorrow. Is it normal for SWG's to have problems keeping up the FC level during the summer?
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    dmanb2b's Avatar
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    Re: Possible Algae?

    Sounds like you have the right plan of attack laid out...it could be a number of things, but the overnight test and a full set of results will help us determine. On thing that comes to mind is that if you have had any water replacement, your CYA may have come down, which may be making it harder for the SWG to keep up with things.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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    duraleigh's Avatar
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    Re: Possible Algae?

    I noticed that the floor was slippery this weekend prior to cleaning and brushing.
    That is sure a strong indicator of algae. I'll bety you get some FC loss tonight when you test.

    Plan to shock.

    I think your swg will return to a more normal setting.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Possible Algae?

    Is it normal for the liner to get slippery? Another question, the pressure on my DE filter has risen very little over the last month and is still no where close to the "dirty" setting. Is there a need to backwash even if there is no increase in pressure?
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    Re: Possible Algae?

    Assume this is an in-ground plaster or pebble pool. How many gallons? How long is the pump/filter operated each day? Is the pool cloudy or clear? Finally, could you post the most recent test results?

    pH
    Free Chlorine (FC)
    Combine Chlorine (CC)
    Total Chlorine (TC)
    Total Alkalinity (TA)
    Calcium Hardness (CH)
    Cyanuric Acid (CYA or stabilizer)
    Salt PPM

    For resolving an algae problem, the most important factors are Free Chlorine and CYA in PPM. If your SWG and filter are working properly and you have been maintaining a Free Chlorine level of 5% or more of CYA, there's less opportunity for an outbreak. E.g. If your CYA is 50 PPM, you'd want a minimum Free Chlorine level of 2.5 PPM.

    Another thing that might help is regularly brushing the boulders in the area where they are getting algae along with your pool.
    30,000 Gallon IG pool, vinyl, Aqua-rite T-cell 15 SWG, 1 1/2 HP with Tagelus TA60D sand filter 60 gpm

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    Re: Possible Algae?

    We did an overnight FC drop test and did not lose any FC or indicate an CC's. Full test results are as follows:

    FC=4
    CC=0
    PH=7.5
    Temp=84
    TA=80
    CYA=60
    CH=70

    The SWG is presently set at 60% and the pump runs from 7:00AM to 7:00PM. We are going to add more CYA to get to a target level of 70. Last summer was our first season with a pool and we didn't keep good records of what our SWG was set at. I just don't remember it being at 60% and only getting 4 PPM of FC. Should we run the pump for a period at night to produce chlorine without losing it to the sun?
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    JasonLion's Avatar
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    Re: Possible Algae?

    Bring your CYA level up to 70 or 80 and everything should be better.
    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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    Re: Possible Algae?

    I was going to add enough CYA to get to 70 but I may as well shoot for 80. I still want to touch on two questions in my earlier posts:

    1. Should I run the pump/SWG at night to generate chlorine without being used up by sunlight? Will this help?

    2. If the pressure does not rise on my DE filter, do I still need to backwash? At the rate my pressure is rising, I will not have to backwash all season.

    Thanks to all!
    Free-form concrete walls with vinyl liner, 18,000 gallon capacity, Jandy 1.5HP e-Pump, Jandy DEV48 DE filter (using cellulose media), Jandy AE2500 heat pump, Jandy Aqualink Power Center with 14-blade cell kit and Jandy PDA-P8 wireless control system.

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    JasonLion's Avatar
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    Re: Possible Algae?

    1) It doesn't make a large difference. If your electrical rates are the same during the day and at night, it is just ever so slightly better to run the pump during the day with a SWG.
    2) Some people only backwash once per season. Unless you have some reason to suspect problems, wait to backwash until the pressure goes up.
    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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