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Thread: Your thoughts on my Pool Math and where to buy supplies please

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    Your thoughts on my Pool Math and where to buy supplies please

    I've been keeping my pool crystal clear, at 88-90 degrees (wife's choice not mine) so far just by monitoring my chlorine levels. Chlorine source is liquid 10% chlorine that I buy for $4.00 a gallon at the local hardware store.

    Haven't been using trichlor or shock for a few months now.

    Recently, I noticed an itchy feeling while in the pool and after. I've also noticed my pool is still clear, but not crystal clear as it was. You can still easily see the bottom drain but it is less clear than it was.

    I ran tests and put the numbers into pool math, here's what I got:

    CH 225ppm
    TA 50
    FC 2.5ppm
    CC 1
    TC 3.5 (corrected)
    CYA 60ppm
    PH 7.2

    I know I'm low on chlorine and have added more to get levels correct but I'm not familiar with some of the other additives recommended.

    Pool math says:
    FC add 46oz of 10% chlorine (done)
    PH 240oz of soda ash or 48oz of Borax (where would I buy that, grocery store?)
    TA 282oz of Baking soda (grocery store again?)
    CH 124oz of calcium chloride or 99oz of calcium chloride diyhidrate (I googled it but am unsure where to actually buy it)

    Before I located and put all these ingredients into my pool, I thought it may be wise to double check here. Seems like a lot of product to me.
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    Mod Squad JVTrain's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Your FC does indeed need to be higher. See the CYA/Chlorine chart in my signature for details on where you should be at for your CYA level. Looks like you're on top of that.

    The CC level is concerning. I NEVER see CC in my pool and the presence of CC in an outdoor pool usually means the FC is actively battling something, algae, bacteria, urine... etc. I would perform an OCLT at an elevated FC level, such as 10-12 FC and post the result. Read here for OCLT instructions: Pool School - Perform the Overnight FC Loss Test (OCLT)

    Borax can be found in the laundry aisle at most any store that has a decent laundry aisle. Baking soda... you got it. Grocery store or anyplace that has baking soda. You can sometimes find large bags/boxes in pool sections at big box stores, but watch the pricing. They stamp "Pool" on the box and triple the price sometimes. Plain old baking soda will do. Speaking of baking soda... what level are you targeting? 50 ppm isn't that bad. If anything, only target 60 to 70 ppm. No sense going any higher. You'll just get faster pH rise.

    The calcium... that's one that you usually have to go to the pool store for. As far as needing to raise your calcium, check out your CSI after you've adjusted all the other levels and not changed the CH. That will tell you whether you need to raise CH or not, but you likely need to... but maybe not a lot. pH has a LARGE affect on CSI. What's your current pH?

    This article has lots of details on pool chemicals: Pool School - Recommended Pool Chemicals
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Pool math says:
    FC add 46oz of 10% chlorine (done)
    PH 240oz of soda ash or 48oz of Borax (where would I buy that, grocery store?) Yes, Walmart 20 mule team
    TA 282oz of Baking soda (grocery store again?)Yes like Walmart, I just picked up 13.5 lb bags at Costco
    CH 124oz of calcium chloride or 99oz of calcium chloride diyhidrate (I googled it but am unsure where to actually buy it) Hardware store/Home depot etc- look for Ice melt like DowFlake
    IG Tear Drop, Dark Gray Gunite , 27,000 gallons -Age 50+-years, very old Hayward Split Egg Sand Filter with side mount Multi-port- Hayward SP2600VSP Pump- Hayward chlorine feed (not used since finding TFP) - Laars 315K BTU Oil heater- LoopLoc Safety cover- AquaBot RAPIDS 4WD- TF-100 Test Kit w/ Speedstir- 390 Gal Hot Springs Spa Envoy installed May 2017

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    You didn't post your pH reading.

    Also, your chlorine numbers don't add up. TC=FC+CC. Your TC is 4, but your FC of 2.5 + CC of 1 only adds up to 3.5.

    I know it seems trivial over 0.5ppm, but if that is part of your CC you most definatly have organics eating up your chlorine.

    Dom
    Dom - TFP Guide
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    DaninFLA's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    I wouldn't adjust your TA unless you are constantly getting low pH. your CH numbers are fine, wouldn't increase it. it will creep up thru evaporation and refills over time.

    only thing you need to worry about is FC...but your CC is concerning.

    I would recommend doing the overnight chlorine loss test (OCLT) asap to see if you have an algae bloom starting. raise your FC to 15 with bleach/chlorine. test after the sun has set and retest before sunrise. your FC loss should be less than 1.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Thanks for the info and pointing out I missed posting the ph level. Currently it is 7.2 and I just edited my original post to include that.

    Other info that may or may not help:
    We have anywhere from 2-4 people in that pool everyday and often a black lab, more on weekends. I'm hoping they aren't peeing in the pool!
    I've been running my pool filter pump 24/7 for a few months and running the polaris pool sweeper daily for a few hours.
    We do seem to get our fair share of bugs and organic matter blown into the pool by the wind but I thought I was doing a good job of keeping up with that.


    Quote Originally Posted by JVTrain View Post
    Your FC does indeed need to be higher. See the CYA/Chlorine chart in my signature for details on where you should be at for your CYA level. Looks like you're on top of that.

    The CC level is concerning. I NEVER see CC in my pool and the presence of CC in an outdoor pool usually means the FC is actively battling something, algae, bacteria, urine... etc. I would perform an OCLT at an elevated FC level, such as 10-12 FC and post the result. Read here for OCLT instructions: Pool School - Perform the Overnight FC Loss Test (OCLT)

    Borax can be found in the laundry aisle at most any store that has a decent laundry aisle. Baking soda... you got it. Grocery store or anyplace that has baking soda. You can sometimes find large bags/boxes in pool sections at big box stores, but watch the pricing. They stamp "Pool" on the box and triple the price sometimes. Plain old baking soda will do. Speaking of baking soda... what level are you targeting? 50 ppm isn't that bad. If anything, only target 60 to 70 ppm. No sense going any higher. You'll just get faster pH rise.

    The calcium... that's one that you usually have to go to the pool store for. As far as needing to raise your calcium, check out your CSI after you've adjusted all the other levels and not changed the CH. That will tell you whether you need to raise CH or not, but you likely need to... but maybe not a lot. pH has a LARGE affect on CSI. What's your current pH?

    This article has lots of details on pool chemicals: Pool School - Recommended Pool Chemicals
    - - - Updated - - -

    Thanks Domct203, you are correct about the math. I actually ran that test twice, once with the help of my son which came up as .5 but I suspected he missed a drop so I re ran it and found it to be 1. Then of course I botched the math.
    Quote Originally Posted by domct203 View Post
    You didn't post your pH reading.

    Also, your chlorine numbers don't add up. TC=FC+CC. Your TC is 4, but your FC of 2.5 + CC of 1 only adds up to 3.5.

    I know it seems trivial over 0.5ppm, but if that is part of your CC you most definatly have organics eating up your chlorine.

    Dom
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    you don't need to run your pump 24/7, especially if its a single speed, that costs a lot of money. If you have a two speed pump and running it on low, 24/7 still not needed but wont cost too much. just need to run pump long enough to have proper chlorination and up to your level of filtering/skimming. many run their pumps for 5 hours or less, others more, just depends on personal preference. just wanted to point that out.

    pH of 7.2 is within range, if you want to slowly raise it, try and get more surface agitation with pointing a return jet near surface. increasing your TA slightly would help this as well. target a TA of 70 for now and with the aeration it should drive your pH up slowly.

    the CC is more likely going to be from kids peeing in the pool and that from bugs, etc.

    CC oxidizes pretty quick, so if you are getting a CC of 1 and its been a few hours since they swam...PEE! check your CC levels right after everyone gets out of the pool and see if they are elevated. if so, need to have the discussion about pee
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Mod Squad kimkats's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    You fixed it. The others have you covered.

    Kim
    Last edited by kimkats; 07-13-2015 at 03:44 PM. Reason: already fixed
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Quote Originally Posted by TCpoolnoob View Post
    Thanks Domct203, you are correct about the math. I actually ran that test twice, once with the help of my son which came up as .5 but I suspected he missed a drop so I re ran it and found it to be 1. Then of course I botched the math.
    It's all good, it's nice to see your son showing interest.

    Don't even worry about TC.

    FC & CC is what we really need, and can assume the TC.

    Dom
    Dom - TFP Guide
    Intex 18' X 48" Ultra Frame AGP 6700 gallons | Two Intex CS8110 SWG's | Hayward Pro Series 21" Sandfilter | Hayward 1.5HP Power Flo Matrix pump | Hayward Thru-wall Skimmer | Wanda the Whale | 72 sq ft of Sungrabber Solar Panels with Hayward GLC-2P-A | Taylor K2006 Test Kit, Sample Sizer & Speed Stir | Click Here To Become a TFP Supporter!

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    After reading what I wrote here, it seems my problem was probably caused by maintaining the FC in the pool too low. I'm not sure where I read it or how I got it in my head but I've been trying to keep it between 3 and 5. After reviewing pool math and the CYA/Chlorine Chart I now realize that is too low. Pool math says 5-9 and the chart says 5-7 for my cya of 60

    Did OCLT last night.
    FC reading 5 at 11:00pm and 3.5 @ 7:30am. That seems like a concerning amount of drop for that short of time?
    I also did the CC test this morning and needed 1 drop to clear the water so .5 on the CC. That's an improvement.

    I brought the pool up to only FC 7 for the day as we have a few guests in the pool right now. Clarity is unchanged, not crystal clear but not fair to call it cloudy I guess.

    My plan is to elevate to shock level (24) with liquid chlorine once the swimmers are gone for the day and perform another OCLT tonight at higher FC levels.

    2 questions about this course of action.

    1. When I raise my pool to FC 24 tonight with liquid chlorine, even if I get no drop overnight, won't the pool be too high on FC for a couple of days to safely swim?

    I'm really not sure how the bagged shock I use to buy actually worked. I'm assuming it quickly raised the FC level but it dropped very quickly as I remember the package saying you could swim in 15-30 minutes after application. I really don't want anymore CYA in the pool as 60 was my target. So I would like to stick with liquid chlorine even if it means a couple of days with no swimming.

    2. If I get a drop on the OCLT over 1 tomorrow, am I going to need to maintain that shock level for a few days until the OCLT shows zero drop?
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    you failed the OCLT, even with the low FC. a loss of 1.5ppm from 5ppm is 30%! if you raise it to 24, you are going to lose a lot more than 1ppm.

    you need to go thru the SLAM process. stock up on bleach! first adjust your pH down to 7.2 if its not already and proceed. you don't need to wait for another OCLT, just get started.

    you can swim in your pool if the level is below shock level, which you don't want during the SLAM. your pool shouldn't take too long, bite the bullet for a few days and get the SLAM completed.

    the key to a SLAM is keeping the FC level at the shock level the entire time. your FC drops really fast during first few days so you will need to stay on top of it as often as you can.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    ^^^^^^^^^^ what he said! LOL

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Boo! But thanks! Heading to the hardware store to stock up on bleach.
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Quote Originally Posted by TCpoolnoob View Post
    Boo! But thanks! Heading to the hardware store to stock up on bleach.
    would buy at least 15 gallons to start. you might need more, but that's a good start. plus you will need it moving forward anyway and the 8.25% stuff will store for a while
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Quote Originally Posted by DaninFLA View Post
    would buy at least 15 gallons to start. you might need more, but that's a good start. plus you will need it moving forward anyway and the 8.25% stuff will store for a while
    Thanks, I bought 10 gallons of 10% at the hardware store. One issue I'm having is that I have put 4 gallons in the pool at one time and it is still only reading about 15 (30 drops) on the test. From where I started, I should be at or close to 24 if pool math is correct.

    I just put another gallon in for good measure.

    I'm concerned I'm not getting an accurate reading on my test or may be getting old bleach? I took it off a fresh pallet at the store but I don't see a date on it anywhere.

    The plus side is the pool now looks totally clear again. Sun is off the pool for the evening, I'm gonna give it a half hour to circulate the new bleach and re run the FC test. I'm hoping I'll be at or very near the same levels in the morning.
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    Mod Squad kimkats's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    There should be a date stamp on the jugs. Please find anything that looks like a inked stamp and post it here.

    We had on person that bought $80 worth of bleach from a big box store. When she added some of it to the pool NOTHING happened on her FC test. We had her add another jug and test 30 mins after and still nothing! WELLLLLLLL she found the date stamp and the bleach was for .......2013!!!!!!!!! It had sat that long at the store. It was water by then. She had her receipt and took all of the empty jugs back and go her money back after some calls were made and facts checked.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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    DaninFLA's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    your 10% has probably degraded to 8.25% im guessing, that and maybe your pool size is off a little bit. both of those could make the math off. plus you have algae which is gonna consume it pretty quick. not unheard of to lose 10-15ppm over 2 hours, so depending how long after you added, it could just be that too. add the chlorine and test 30 minutes later and see where you are at.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Your thoughts on my Pool Math and where to buy supplies please

    Last night I got FC to 25, checked at 9am and it was down to FC 17.5. I have not detected any cc in the last 4 tests or so.

    Pool math said add 1.5 gallons to get back up to 24 so I put in 2 gallons. Don't have time to wait around and test it right now but will within an hour or two.

    Good news is the pool is crystal clear again.

    Will I need to keep the FC to shock level all day and then check for a drop overnight? Looks like you all helped me catch this very early and it has turned around quickly.

    - - - Updated - - -

    Quote Originally Posted by kimkats View Post
    There should be a date stamp on the jugs. Please find anything that looks like a inked stamp and post it here.

    We had on person that bought $80 worth of bleach from a big box store. When she added some of it to the pool NOTHING happened on her FC test. We had her add another jug and test 30 mins after and still nothing! WELLLLLLLL she found the date stamp and the bleach was for .......2013!!!!!!!!! It had sat that long at the store. It was water by then. She had her receipt and took all of the empty jugs back and go her money back after some calls were made and facts checked.

    Kim
    Will do, It is HTH brand and sold in a cardboard box containing two 1 gallon jugs of 10%. I was mindful of age as I bought it from a local ace hardware store. They've had 1 pallet there for several weeks but I pulled this off of a brand new pallet only missing a couple of boxes. I was hoping I was getting the fresher stock. The only stamp I see is on the box and it's a short code. I'll post that up later today.
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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    DaninFLA's Avatar
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    Re: Your thoughts on my Pool Math and where to buy supplies please

    you can try to OCLT test tonight, but you probably will not pass. probably need a few more days. need to keep your FC at SLAM level as much of the day as you can, one way to help with that is to overshoot your initial FC a bit. if your level is 24, go to 28 or so. will give you some buffer.

    in the mean time you need to brush the pool a couple times a day. I would also advise you remove the light fixture from the niche and clean that out as well. the cavity behind the light doesn't really get water flow and can grow a lot of algae and has delayed/stalled many SLAMs. get the light out and just leave it on the side of the pool until the SLAM is complete.

    just because your water is clear doesn't mean you are done. this is the time to finish it off and kill all the bacteria. if you stop now it will come back. keep at it and do not stop until you pass the OCLT.
    Dan
    9,000 gallon in-ground Saltwater pool, plaster, cartridge filer, 1.0 hp pump, Hayward T-15 SWCG, TF-100
    Pool School - Chlorine / CYA Chart; Pool School - Test Kits Compared;

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    Re: Your thoughts on my Pool Math and where to buy supplies please





    Here's the only thing I've been putting in the pool for the past couple of months.

    I just checked the FC level and it was only 22-23. I put another gallon in to get over shock level just now. Won't be able to monitor it again until the evening. I'm thinking either I have misjudged the pool volume or this batch isn't as strong as it is supposed to be. So far I've put 8 gallons of the new stuff in. I'm gonna see if I can pick up some more effective bleach today.

    Quote Originally Posted by DaninFLA View Post
    you can try to OCLT test tonight, but you probably will not pass. probably need a few more days. need to keep your FC at SLAM level as much of the day as you can, one way to help with that is to overshoot your initial FC a bit. if your level is 24, go to 28 or so. will give you some buffer.

    in the mean time you need to brush the pool a couple times a day. I would also advise you remove the light fixture from the niche and clean that out as well. the cavity behind the light doesn't really get water flow and can grow a lot of algae and has delayed/stalled many SLAMs. get the light out and just leave it on the side of the pool until the SLAM is complete.

    just because your water is clear doesn't mean you are done. this is the time to finish it off and kill all the bacteria. if you stop now it will come back. keep at it and do not stop until you pass the OCLT.
    Thanks, I'm going to take your advice to brush the pool and remove the light as well. The walls and floor of the pool look as clean as they ever have to me but I want to make sure everything is dead and gone so I don't have to do this again this season.
    24,000 gal in ground, Gunite, Sand filter, Hayward 140,000 btu heat pump, Pentair Superflow VS, Polaris pool sweep, TF-100 test kit w/speed stir

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