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Thread: Fc from 6.5 ppm to 0 ppm

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    Fc from 6.5 ppm to 0 ppm

    I need some assistance. My FC just dropped from 6.5 PPM TO 0 PPM within 24 hours. There has been no rain, my heater is off, etc The only thing I did was to add a stain remover yesterday morning. Could the stain remover cause such a drop on FC? or could it cause false reading? Please help....I do not know what to do.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Fc from 6.5 ppm to 0 ppm

    What stain remover did you use? Does it have any of the ingredients listed on the bottle?
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
    Pool School - PoolMath - HIGHLY Recommended Test Kits

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    Re: Fc from 6.5 ppm to 0 ppm

    Stain removers are usually ascorbic or oxalic acid and are reducing agents which will neutralize chlorine.

    What specific product did you add and how much?

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    Re: Fc from 6.5 ppm to 0 ppm

    Hi!

    I used 2 lbs of Pool Stain Treat by United Chemical. It does not list any chemicals, but does not mention anything about reducing chlorine. It does mention that it could lower the PH levels. My PH was 7.9 prior to adding the pool stain treat and now PH is 7.5.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Fc from 6.5 ppm to 0 ppm

    That would be Oxacilic Acid and it is exactly what dropped your FC level. Before doing strain treatments it is highly recommended to allow the FC level to drop (and potentially add a polyquat algaecide to prevent algae during the treatment) because they will just react with each other. Oxacilic acid is also less optimal than Ascorbic acid because of the possibility of it reacting with calcium in your water, forming Calcium Oxalate and clouding it up.

    Here are instructions on AA stain removal. Keep in mind that the purpose of AA treatment is to remove the stains, the metal will remain in the water and need to be sequestered unless you change a significant portion of the water.
    Ascorbic Treatment to rid Pool of metal stains
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
    Pool School - PoolMath - HIGHLY Recommended Test Kits

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    Re: Fc from 6.5 ppm to 0 ppm

    Pool stain treat is oxalic acid and will reduce chlorine. Bring the chlorine back up slowly and carefully. Don't shock as that can cause the metal stains to drop back out. Add a quart of poly 60 algaecide and a quart of good sequestrant.

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    Re: Fc from 6.5 ppm to 0 ppm

    How do I know if the stains are metal or not?
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Fc from 6.5 ppm to 0 ppm

    Quote Originally Posted by RESISTENCIA13 View Post
    How do I know if the stains are metal or not?
    One way is to hold a vitamin C tablet against one to see if it lightens the stain. A little background might help us help you identify them, when did these start to appear and have you added any algaecide recently? Can you post a picture and/or describe them?
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
    Pool School - PoolMath - HIGHLY Recommended Test Kits

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    Re: Fc from 6.5 ppm to 0 ppm

    I would think that if the stain remover you added works, that's a good indicator that the stains were metal.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    Re: Fc from 6.5 ppm to 0 ppm

    My pool was built last year. I do not know when the Spa was stain. I just noticed it a few weeks ago. Attached is a picture of one dotted stain and the rest is just the walls being yellowish. I have never add any algaecide to my pool.

    - - - Updated - - -

    Well....I still have the stains.

    Quote Originally Posted by pabeader View Post
    I would think that if the stain remover you added works, that's a good indicator that the stains were metal.
    Last edited by RESISTENCIA13; 09-27-2015 at 06:46 PM. Reason: ADD ANSWERS
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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