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Thread: combined chlorine test question

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    combined chlorine test question

    I have been in SLAM process for over a week with little results. Pool still not clear at all. 4 ft pool 14000 gallons and can only see down about 2 feet but it is blue, not green. Combined chlorine has always come up .5 or less. Today I did the test and put in R-0003 from the TFT-100 test kit after figuring out my FC and it was clear or less than a drop would have cleared it. I then finished eating and forgot to dump the water so then about 10 minutes after completing the test the tube has pink water... do you have to wait awhile after adding the reagent or look at it immediately. Does letting it sit give false positive?
    CYA high -80 so we have been maintaining a chlorine level of 31 and starting to run out of drops and getting frustrated.

    This is a new house to us and not used to pool. We live extremely close to a flour mill. Any chance it is dust and too fine for our sand filter to really get it out?

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    Patrick_B's Avatar
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    Re: combined chlorine test question

    Pay no attention to the test after it sits more than a minute or two. Slam often takes more than a week, so you may not have any issues other than just waiting it out. You might try adding DE to your sand filter to speed the process. There is a tutorial in Pool School on how to do it.
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    Agent99's Avatar
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    Re: combined chlorine test question

    You want to do it right away...don't let it sit.

    Can you post pics of what you are dealing with?

    Are you passing the OCLT (Overnight Chlorine Loss Test)? You shouldn't lose more than 1 ppm overnight.

    Have you ever checked for metals in your water?
    ----Chris----
    25k IG/Spa Figure 8, 18x36, Pebble Sheen Blue Granite, Sta-Rite S8M150 Cartridge Filter, Pentair 460805 400k BTU Heater & 011018 IntelliFlo VarSpd
    Liquidator, Fafco Solar Heat, Polaris PB460 Booster Pump w/280 cleaner, Katchaleaf Cover, TF100 Test Kit, FAKE MAIN DRAIN

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    Re: combined chlorine test question

    picture of pool showing steps or ladder would be great!
    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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    DaninFLA's Avatar
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    Re: combined chlorine test question

    to save on reagent when you are testing high FC values, fill your tube to 5ml and each drop is then 1ppm of FC. not nearly as accurate as testing with the 10ml, but when you are at 30+ I think its ok. plus counting to 60 can be difficult too
    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: combined chlorine test question

    Quote Originally Posted by cherylt327 View Post
    Does letting it sit give false positive?
    If you wait long enough, oxygen in the air can dissolve in the water sample and react with DPD. So you don't want to wait too long after adding the DPD powder before finishing the test.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: combined chlorine test question

    IMG_0720[1].jpgIMG_0719[1].jpg
    Here are some images I also took a water sample this morning and put it in a clear bottle to see what would fall out and it looks the same as it did this morning and appears to be clear with nothing at the bottom 10 yours later
    IMG_0718[1].jpg
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    In regards to metals before I found tfp I had taken sample to pool store. They stated Iron was .7 and copper .1 They sold me 2 bottles of some metal stain remover or something and I was supposed to use a bottle and half. I put in one bottle and figured see what it did first. Pool didn't look better and tried the other pool store in town then. They said iron .3 but copper 0 and that was after the other treatment. The second was bioguard deale-Alex system and first uses clearcare expert computer program. One of the pool stores had my pool down as 17000 gallons and other had 13000 and I measured it to be 14000. The tft-100 kit doesn't measure for metals does it so I can't measure for them on my own.
    The mill produces a brown dust supposedly that settles on the pool floor and easy to vacuum according to the old owner. I saw it when we looked at house and it vacuumed right up not stuck to floor at all when he showed us how to use the pump. No brushing was needed. I cant see the bottom of my pool but figure that is what is settling on my ladder some. I have been brushing and vacuuming daily even though we can't see what we are doing and only skipped one day as couldn't help it but chlorine was still tested that day. The pool is in full sun all day.
    Last nights OLCT was 0. We loose quite a bit during the day 6ppm but the pool is in full sun (the solar cover in pic is shot and is giving off little plastic pieces so it is not used.) Been trying to maintain FC at 31 since CYA is 75-80
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    Ha! You've been reading! May I assume you took the ladder and scrubbed it underneath? If your OCLT was good, it may be time to try adding some DE to your filter.

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    Re: combined chlorine test question

    bought a bag of media for de filters .. hope it is right. put some in filter and first time seemed to get white blown out but second time it was ok. Hopefully it will help. Overnight chlorine loss was zero, combined chlorine is zero but still cloudy
    Really need it clear for next weekend birthday party.
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    Is it still cloudy like your last picture?

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    Re: combined chlorine test question

    Yes still looks pretty well like the picture. Very cloudy. I been taking pictures of the steps every day and haven't really seen too much improvement. Only put the DE early this afternoon though so hoping overnight it will yield some better results
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    How much did your pressure rise after you put in the DE?
    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: combined chlorine test question

    We put in enough to let it rise 1 after just a few minutes and quit adding so managed less than a cup. The psi is up 4 now from normal (what we assume is normal - what it was right after our backwash)
    We even changed pressure gauge today because wasn't sure we could trust old one and it had condensation in the inside so it was difficult to read anyways.
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    Normally, you should add a little, check in a half hour, add a little, check in a half hour, etc. until your pressure goes up only by 1psi. You MAY have put in too much.

    Keep an eye on your gauge and be prepared to backwash tonight if it rises 25% over "clean (pre-DE) pressure.

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    Re: combined chlorine test question

    We had originally done that quit when the pressure when up by one. We ended up backwashing this morning as pressure had gone up so more but think it because it actually filtering junk from the water. We could see the fourth step today so that was an improvement -- couldn't see it clearly but could see it so progress finally. We have had 0 chlorine loss overnight for past 2 nights. combined chlorine is 0. Should we let the chlorine levels go down or keep them up until water is clear? Water is still cloudy but after adding the DE we are finally seeing progress and hopefully it will be clear by the weekend birthday party and hoping our IL weather holds out and we get some warm days. The cold rain really brought our pool temp down the other day.
    18x33x4 oval Above ground pool- 15300 gallons, sand filter, full sun no shade
    tft-100 test kit
    Central Illinois

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    Re: combined chlorine test question

    I would keep up with the chlorine, brushing, and the DE.
    The weather looks great this week here in IL, although we could use some rain.

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