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Thread: FC high CYA low

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    malibu's Avatar
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    FC high CYA low

    Learning how to balance. First time pool owner, first filled June 2015.
    Only was testing with simple kit. No issues visible. Chlorine read about 4 and pH about 7.8.
    SWG running at 50% entire time. Pump running 8am-4pm.
    I added too much salt on 7/10, I misunderstood amount and Salt was up at 4800ppm. Since then have added water over time and it is now 3900ppm.
    Throughout July and August pH stayed about 8, added maybe 30oz dry pH Down over that time. Water temp stayed about 80'.
    Purchased and started testing with TF-100 kit:
    9/3/15
    CH 250
    FC 7.5
    CC .5
    TC 8
    TA 140
    CYA 25
    pH about 8.2
    Chlorine about 5
    added about 20oz pH Down.
    Water Temp 78'

    9/8/15
    CH 250
    FC 9
    CC 0
    TC 9
    TA 140
    CYA 24
    Chlorine 5
    pH 8.1

    9/17/15
    Put solar pool cover (bubble wrap type) on main body of water, not the river or spa
    Water Temp 72'

    10/4/15
    CH 225
    FC 13
    CC .5
    TC 13.5
    TA 120
    CYA 20
    Chlorine 5+ more Gold looking than yellow
    pH 8.2
    Cut cover to fit better, and added large section to almost all of river and half spa covered.
    Water temp about 76'

    10/7/15
    Added about 1/2 gallon Muriatic acid

    10/8/15
    CH 250
    FC 20
    CC .5
    TC 20.5
    TA 120
    CYA 20
    Chlorine 5+ gold looking
    pH 7.8
    Water temp 74'

    Uncovered 10/9/15 for most of the day and waterfall running.

    I'm worried about CYA and too much Chlorine.
    Should I be?
    I have been comparing with Pool School and obviously I'm not close on some readings.
    I was hoping adding Muriatic Acid to lower pH would affect the other readings.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    Welcome to TFP!!

    With a SWCG pool you want to bring that CYA up to about 60 at least. But, with that being said it is safe to swim in water with the FC up to shock level which for your CYA 20 would be 10. So, 10 and under you are fine. Above 10 we would not recommend swimming, but to be honest it's harder on the swimsuit than the skin. You will start to see fading of the suits and degradation of elastic.

    See this chart for our recommendations: Pool School - Chlorine / CYA Chart

    Muratic acid is going to reduce pH and to a lesser extent TA but will have minimal effect on anything else.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Welcome to the forum.

    The most important thing about your test results is leaving the pH above 7.8 Don't do that.

    Bring it down into the seven's and keep it there,

    read "The ABC's of Pool Water Chemistry" up in Pool School. It'll give you guidelines on where your parameters should be.

    Once you get a grip on your pH, add enough CYA to get to 60 ppm.

    What does your water look like?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    malibu's Avatar
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    Re: FC high CYA low

    Water looks nice and clear, looks like when it was first filled.
    I have been reading the guide but not sure the order to adjust levels. I assume top down?.
    So first is my Salt ppm, with is at 3900, not recommended 3400, should I keep adding water to drop it down? I found that if I drain some water out at the pump, the Salt level goes up, but if I add water from hose the level drops as the overflow drains the excess water. I live in the city so on city water.
    Should I go ahead and add more Muriatic Acid to lower pH more? I added half gallon before and it dropped pH 8.2 to7.8.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    Add more acid now. Use Pool Math to try to calculate how much. Pool Math

    If your salt is a little high but the cell is working I wouldn't worry about the salt at this time.

    Of importance pH & FC all the time - at the top of the list. Check these daily until you learn your pools habits.

    Bring the CH & CYA up, you can do them at the same time. When adding CYA don't try to add it all at one time. Break it up into stages so you don't overshoot. I would see how much you need to go from your 25 to 40, measure that amount and place it in a sock (the kind you wear on your feet). You can either suspend it in front of a return or place the sock in a skimmer as long as it does not obstruct all the water flow. Give it a squeeze every now and then to help it melt. Don't bother testing for at least one week as it takes time to appear on the test.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Ok Thanks very much.
    I will add acid tonight, run the pump for an hour, and test pH and FC tomorrow.
    I will get both calcium chloride for CH and solid stabilizer for CYA.
    By the way I used to have an above ground hot tub. I still have 16oz liquid Sea Clear Spa Calcium Increaser. is that safe and ok to use?
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    Quote Originally Posted by malibu View Post
    I still have 16oz liquid Sea Clear Spa Calcium Increaser. is that safe and ok to use?
    I wouldn't use it. The MSDS sheet shows 50% ofthat is "Trade Secret" and only 28-42% is calcium chloride. I don't know what that 50% is so I wouldn't use it.

    http://www.halosource.com/HaloSource...mIncreaser.pdf
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Ok wow, thanks for that info.
    Glad I didn't.
    Thanks again.
    I will add acid and check readings tomorrow.
    I will try to get the other two items tomorrow and add on Monday. I will wait a week and post new readings.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    Quote Originally Posted by malibu View Post
    Ok wow, thanks for that info.
    Glad I didn't.
    Thanks again.
    I will add acid and check readings tomorrow.
    I will try to get the other two items tomorrow and add on Monday. I will wait a week and post new readings.
    Just stay on top of the pH & FC during the week. Those change quickly.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Added about 1 1/2 lbs of Cyanuric Acid on Monday, added another 1 1/2 lbs Cyanuric Acid on Wednesday as per amount recommended by the Pool Calculator. Today tested pH 8.2 and Chlorine which was Orange, not even a yellow close to the measurement. My Salt ppm was 4100. Tested FC 26. I have the cover on which covers about 90% of the water this whole time. Not planning to test CYA until next Monday since I should wait about a week. Day time highs have been in upper 80's all week, and lows in the mid 50's.
    Should I add MA to lower pH? Also what about the chlorine level? Just keeps rising. SWG is still set at 50% with pump running 8a-4p.
    Haven't added Calcium yet.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Re: FC high CYA low

    You say FC was "orange" which tells me you are using the OTO yellow drop test in the blue box. Use the FAS-DPD test (powder test) which will give you results up to 50 FC.

    Yes, use acid to get the pH down into range. Like I said before, test pH & FC daily and adjust as necessary. Those are the things that move quickly.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    When I did the FC test it was almost red in the Chlorine only tube. When I did the Chlorine test along with the pH test using the tester in the blue box, the color was orange. I didn't use the powder.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Re: FC high CYA low

    Quote Originally Posted by malibu View Post
    When I did the FC test it was almost red in the Chlorine only tube. When I did the Chlorine test along with the pH test using the tester in the blue box, the color was orange. I didn't use the powder.
    You had ot put the powder in the tube to turn red, didn't you? The FAS-DPD test?

    This Test
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Yes. I then had to add 52 drops of the R-0871 to turn it clear. It was very Magenta and close to red after I put the powder in. I swirled while I added the R-0871.

    - - - Updated - - -

    Yes. I added the powder, then had to add 52 drops of the R-0871 to turn it clear. It was very Magenta and close to red after I put the powder in. I swirled while I added the R-0871.
    I did two tests. One was the Chlorine test when I did the pH test using the tester in the blue box, I added 5 drops of yellow for the chlorine.
    Then I also tested the FC using the Chlorine Only tube from the kit with the powder.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    I would turn of the SWCG for a day or two to get the FC down and then when you turn it back on reduce the % or reduce the runtime each day.

    When you do the FAS-DPD test there is no need to do the OTO test. The OTO tops out at 10 and if you are already doing a more precise test no need to bother with the other one.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    Ok. Thanks for your help. I was using the OTO to check the pH but also wanted to check Chlorine since I have seen the color change, it was getting more gold over time and now has gone more orange. Just a familiarity.
    I will add Acid in the AM per amount on the calculator. I will also turn off the SWG for the weekend. Monday I need to test CYA so I will test everything then. I will lower the SWG to 40%, same run time, and check again on Tuesday.
    Just a side question, could the rise in Chlorine occur because of the cover? Does it keep the off gases trapped and affect the chlorine?
    I was reading on another post that I should remove the cover as we get into colder days and nights. I think someone in California said they use their cover for September and October and then again in April and May to keep the temp up so it is swimmable. I like to use the Spa during winter so I don't think I need to winterize, right?
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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    Mod Squad tim5055's Avatar
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    Re: FC high CYA low

    When FC is above 10 pH is going to read incorrectly high.

    If you keep the pool covered all day you FC is going to continue to rise. FC is degraded/depleted by two things - organics in the water and UV rays of the sun. If you have little/no organics and keep the pool covered the FC will keep rising.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: FC high CYA low

    The solar pool cover thing is confusing. Sure it keeps the water from evaporating which I have noticed, but it blocks the sun some. I thought it would affect the chlorine especially when I notice the chlorine smell when I remove the cover to brush it. I think I will slide it over to mostly off the pool during the day, back on in the evening. That should help bring the FC down quicker as well as turning off the SWG.
    New free form in ground salt water pool about 13,000 gallons, first filled 6/16/15, plaster, waterfall, spa flows into pool, all Pentair, 4 filter cartridges, IC40 SWG, (2) 3 hp variable speed pumps, Master Temp 400 heater, Booster Pump 1.1hp, my first pool, using tf-100 kit

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