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Thread: Is it normal to lose this much FC in one day?

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    Join Date
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    Is it normal to lose this much FC in one day?

    My CYA is 60, so I try to maintain a FC level of 7. PH is 7.6 and TA is 120, CC is 0, and lastly, it is an outdoor 22,500 gallon pool in the north Texas heat. But, my water is clear.

    Anyway, I will add chlorine at night to get my levels up to 7 and by the following evening they may be as low as 2.5 to 3. In the morning they will be around 6, but by the end of the day they are much lower. My CYA used to be 30 but I upped it to keep the sun from burning it off as fast, but it seems to have not made any difference. Is a drop in FC by 4 points a day normal for 95 degree Texas summer heat, or do I have something else consuming the FC (algae) that just hasn't altered the clarity of the water yet?

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    Mod Squad YippeeSkippy's Avatar
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    Re: Is it normal to lose this much FC in one day?

    4ppm loss is on the high end of possible, but one way to determine if there is something in the water chewing it up is to perform an OCLT (overnight chlorine loss test) and see how it comes out- Overnight Chlorine Loss Test

    If nothing shows up on the OCLT, I'd raise my daily goal to 8 or 9 and see if that helps you not bottom out so far down. Your bottom line acceptable FC is 5ppm, lower than that and you're at high risk for algae.

    Yip
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
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    Re: Is it normal to lose this much FC in one day?

    Yeah I've done that with no more than 1-1.5ppm loss. It must just be too hot here.
    17x33 Splash Alpha Pool, Pentair Tagelus TA60D sand filter, Pentair 1.5HP Dynamo Pump. Pool ladder, towel hooks, ice chest full of beer, green swim trunks.

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    Re: Is it normal to lose this much FC in one day?

    durtynacho

    I'm in Dallas County, just north of you with a 15k gunite outdoor pool (no SWG) . Here's my typical #'s :

    CYA 50 I usually maintain it between 40-50 .
    FC Range 4-8.5 I like to target the max dosage about 0.5 higher than my FC/CYA range max.
    FC daily loss: It varies with the season but generally in the summer, it depletes between 2.0 / day to 2.5 / day .

    My pool is shaded for approx. 1/3 of the day.
    - Pool Type: 15k Gal Gunite IG non-SWG / Built 1988
    - Pump: Pentair Challenger / Sweep Pump: Letro Model LA01N .75HP Single-speed / 6 hrs-day (1 turnover)
    - D.E. Filter: OEM: Nautilus (Pentair) #NS 36 / 36 Sq Ft / D.E. Charge: 3.6 Lb
    - Pentair 4-wheel Sweep LL505G - Booster Pump runs ~2 hrs/day

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    Re: Is it normal to lose this much FC in one day?

    I did the OCLT and went to bed at 6.6, woke up at 6.6, so it really must be the heat. My pool is in full sun pretty much all day, so a loss of 4ppm might be normal for this time of year.

    Anyway, at least I know it aint algae! Thanks everyone for the replies.
    17x33 Splash Alpha Pool, Pentair Tagelus TA60D sand filter, Pentair 1.5HP Dynamo Pump. Pool ladder, towel hooks, ice chest full of beer, green swim trunks.

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    JoyfulNoise's Avatar
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    Re: Is it normal to lose this much FC in one day?

    My routine daytime temps are 105F and my pool routinely hovers in the high 80's (86-89F) and my pool gets direct sunlight from 8am to 5pm. My daily FC loss is around 2.3ppm/day. I also have an SWG pool and I keep my CYA up at 80ppm.

    Your higher FC loss is likely UV related not heat related. Your water would have to be up in the mid 90's for temperature to start playing a significant role.

    Increase your CYA if you want to reduce UV loss.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Is it normal to lose this much FC in one day?

    Quote Originally Posted by durtynacho View Post
    I did the OCLT and went to bed at 6.6, woke up at 6.6, so it really must be the heat. My pool is in full sun pretty much all day, so a loss of 4ppm might be normal for this time of year.

    Anyway, at least I know it aint algae! Thanks everyone for the replies.
    I am close with you, I am loosing 3.5ppm per day right now, CYA 40-50 and pool water is 92, full sun for 8+ hours
    Valley of the Sun, Arizona.....10k gunite/pebble (Re-surface March 2015) w/in floor Caretaker 99 cleaning heads -- Pentair FNS 60 DE filter -- Pentair IntelliFlo Variable Speed for pool -- Pentair Wisperflo 1 HP for boulder waterfall...Taylor K-2006 & Taylor K-2006C kits

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