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Thread: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

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    UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    Hot and humid here for the last week or so. I was holding FC at 3-4 before the heat set in. In was running my IC40 10 hrs a day in my 44.5k gallons pool with it set on 80%. About two days ago I adjusted the run time to 12 hours and 90%. Last night checked it and the FC was 1. I added 2 gallons of leftover bleach from last year. This morning I checked it and the FC was 4.5.

    I wonder if the cell is degrading or is the heat just getting the best of the FC level. I am running ph of 7.6, TA of 50, CH of 125, CYA of 50, and salt is 3400-3600.

    Thoughts or recommendations?
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: FC dropping during hot days! Bad cell or normal?

    The heat is getting the best of me right now. Chlorine consumption has shot up and I am holding off raising my CYA since I am going on vacation next month and need to use pucks.

    I think your CYA is too low. In saltwater I believe they say 70-80.
    16x32 IG rectangular 21,800k new vinyl liner 2014, Triton II TR 50 sand Filter, Pentair 3/4 hsp whisperflow pump, 3 returns, TF100 test kit w/speedstir. Maytronics s 300i robot.

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    Re: FC dropping during hot days! Bad cell or normal?

    CYA for SWG pools is 60-80. Your swg is struggling at the low levels. Boost CYA and see if that helps.
    COMPLETED BUILD THREAD - 15'x29' rectangular offset shotcrete pool; 14,100 gal; 5'x7' raised spa with 400k btu fire feature; 7' spillover; 25' leuder stone raised bond wall w/waterfall; Pentair SWG; Pentair VS (pool); Pentair 3/4hp feature pump; 1hp spa blower; Pentair Cartridge filter; Pentair “Easy Touch 8” wireless; Dolphin Oasis Z5 robot; Solar Hydronics iSwim solar panels; Mansard Screen Enclosure; walnut travertine deck; 1 very happy kiddo.

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    Re: FC dropping during hot days! Bad cell or normal?

    Just wondering if the algae has gotten the better of you. It sounds like you have let your FC drop too low. Might be worth an OCLT to see whether it is something your going to need to hit up with a SLAM.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
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    Re: FC dropping during hot days! Bad cell or normal?

    I really don't think it's an algae attack. I pretty much test my water daily and yesterday was the first day it's been at 1. T

    Think I might should raise cya now or do an OCLT night and see what that yields. If I remember right if he cya is lower when SLAMMING it requires less FC levels.
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: FC dropping during hot days! Bad cell or normal?

    Well an OCLT will tell you one way or the other- so I would do that first before adding any CYA in. If you do end up having to SLAM then you will need more chlorine for the higher CYA level.

    I'm truly hoping that your right and that you don't have any algae- I've been caught out like this a couple of times before in hot weather.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
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    Re: FC dropping during hot days! Bad cell or normal?

    About two days ago I adjusted the run time to 12 hours and 90%. My cya was 80 the only time I had to do a SLAM and it took a bunch of bleach to get it under control.

    I'll do the test tonight.
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: FC dropping during hot days! Bad cell or normal?

    Well I passed the OCLT so it looks like I need to up the CYA to around 70.

    Agree?
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: FC dropping during hot days! Bad cell or normal?

    That's great news gobblerhuntr.

    Yep crank it up -I would go for 80. Possibly in 2 steps if your worried about overshooting.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
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    Re: FC dropping during hot days! Bad cell or normal?

    +1 to going to 80 on CYA. CYA at 80 will lower your FC consumption noticeably .
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    Re: FC dropping during hot days! Bad cell or normal?

    Yesterday my FC got to 1.5-2 so I added 2 gallons of bleach and did an OCLT. Last night the FC was ~5 (took 10 to 11 drops to clear up water) and this morning it was ~4-4.5 (took 9-10 drops to clear water). MY CYA is still around 50 as I haven't bumped it up yet. I need to either bump it up or SLAM?

    Recommendations?
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    Keep raising CYA to 80. Dial back SWG slightly to maintain FC
    COMPLETED BUILD THREAD - 15'x29' rectangular offset shotcrete pool; 14,100 gal; 5'x7' raised spa with 400k btu fire feature; 7' spillover; 25' leuder stone raised bond wall w/waterfall; Pentair SWG; Pentair VS (pool); Pentair 3/4hp feature pump; 1hp spa blower; Pentair Cartridge filter; Pentair “Easy Touch 8” wireless; Dolphin Oasis Z5 robot; Solar Hydronics iSwim solar panels; Mansard Screen Enclosure; walnut travertine deck; 1 very happy kiddo.

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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    Just asking the obvious- did you switch your SWG off when you performed the OCLT?
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    Quote Originally Posted by Jezza View Post
    Just asking the obvious- did you switch your SWG off when you performed the OCLT?
    Yes my pump run time stops at 8 pm and I did all test after 8 pm and before the pump kicked back on at 8 am.

    That is correct right?

    - - - Updated - - -

    Quote Originally Posted by txnole View Post
    Keep raising CYA to 80. Dial back SWG slightly to maintain FC
    I have the SWG set at 90% now. If I raise the CYA shouldn't I wait until the SWG is producing more FC than is used in a day then dial it back?
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    To conduct a reliable FC test in the morning you really need to have the pump running beforehand- ideally around an hour to make sure the pool is mixed. You also don't want to wait too long between the pump turning off and testing at night. So this is what I would do

    Test at night either with pump still running or straight after pump turns off
    Set the pump to come on while for an hour before testing, allowing yourself enough time to test before the sun comes up

    Also yes keep the SWG dialled up until you are confident that it is producing enough chlorine to maintain the correct FC for your CYA. When you are ready to move up to CYA of 80, then you need to closely monitor to ensure the SWG is keeping up with the required FC level. Remember you don't ever want to drop below the minimum FC. You could also consider adding an extra boost of bleach to help out the SWG.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    I have read that taking a sample directly in front of a return while SWG is on to see if you have a higher concentration. I keep my CYA at 80 in the summer and FC maintains around 6. Right now cell is at 75% and run time is about 6 or 7 hours a day. I only get about 6 - 7 hours of sun on the pool each day. If indeed your cell is going bad (check for scale) and you need to replace, you probably want to go to IC60 your cell may not be able to keep up with your size of pool.
    18x36 kidney 20,000 gallons IG vinyl. Pentair Easy Touch 8 w/IntelliChlor IC40. Triton II TR100. Pentair Intellifllo Variable Speed. Waterfall/Jump Rock. 2 Pentair Intellibrite lights. TF-100 Test Kit. And a very happy husband who gets to play in the pool without having to take care of it.

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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    The pump should be running for the OCLT at least an hour after adding for your double check to see you reached your target, and a half hour to hour before your morning check with the SWG off the entire night.
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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    Every pool is different, but we get 10-12 hours of sun, pool water at 86, CYA at 70 and SWG at 27% to average 5-6 FC.
    COMPLETED BUILD THREAD - 15'x29' rectangular offset shotcrete pool; 14,100 gal; 5'x7' raised spa with 400k btu fire feature; 7' spillover; 25' leuder stone raised bond wall w/waterfall; Pentair SWG; Pentair VS (pool); Pentair 3/4hp feature pump; 1hp spa blower; Pentair Cartridge filter; Pentair “Easy Touch 8” wireless; Dolphin Oasis Z5 robot; Solar Hydronics iSwim solar panels; Mansard Screen Enclosure; walnut travertine deck; 1 very happy kiddo.

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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    is it just me or does the op have a barely sufficient swg? IC40 for a 44,000 gallon pool? I would not expect that to be sufficient.
    16x32 IG Vinyl, 13,000 Gals. Hayward S-244T sand filter, SP2810X15 pump
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    Re: UPDATE HELP PLEASE: FC dropping during hot days! Bad cell or normal?

    I have always thought I needed an IC60.

    Last night I added CYA and let the pump run all night to mix it. I tested the FC right after the pump shut off at its normal time and it was 3.5. This morning after running all night the FC was 3.5, that doesn't sound right to me. My cell has never had any scaling whatsoever and has been cleaned several times.

    My pool started out as a 20'x40' then put Roman ends on each end so I consider it approx. 20'x48'x6' deep on average. Do y'all think that would be correct diminsions?

    I now wonder if an IC60 will fit where the IC40 is?
    20x49 double roman 3.5' to 8.5 deep', 44,000 gal. SWG, TF-100 test kit with speed stir, concrete walls with vinyl liner, cartridge filter on an IG pool with a 1hp main pump and 1.5hp booster pump. Pool built April 2013

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