Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 9 of 9

Thread: OCLT and testing consistency

  1. Back To Top    #1

    Join Date
    Jun 2013
    Location
    Central Texas
    Posts
    9

    OCLT and testing consistency

    I have been lurking for a while now, and I have been on BBB for a couple of months now. This site is an awesome resource, and the people are great! Thanks so much!

    After getting a lot of rain the past few weeks, I became concerned after seeing what appeared to be the beginnings of algae growth, in spite of never allowing FC to drop below 5. It looked like grey dust on the bottom that would disappear when brushing. It also felt neither slimy or gritty, so I decided to go ahead and SLAM and have done so for the last four days. After the first day of SLAMing, no more sign of "algae", and I have continued to maintain shock level until last night. Filter has been running 24 hours/day. The pool has been looking crystal clear through the entire SLAM process and continues to look great.

    My test results this morning:
    FC 16
    CC 0
    PH 7.5
    TA 100
    CH 280
    CYA 50-60 (I'm assuming 60)
    Borates 40-50

    Also, I lowered PH to 7.2 before starting the SLAM process

    Now for my real question. Last night my FC was 14 (CC 0), and I did not add any chlorine to the pool, yet it read 16 this morning. Any ideas why FC would read 2 ppm higher? I have tried to be careful with my testing, always taking the sample about a foot deep in front of the skimmer. I am also trying to be careful with the drops to make sure I don't go too fast or too slow (no more than about 1 or 2 per second). One other important fact is that I installed a HASA Liquidator a couple of weeks ago, but I have had it shut off during this entire SLAM process (the flow indicator is at zero and I see no water movement in the 3/8" tubes).

    Thanks,

    Dennis
    15.5K gal, IG vinyl, Hayward 1/2 HP, AquaView 3.14 sq ft sand filter (above ground pool installed in ground, so no main drain), TF-100 test kit w/SpeedStir, BBB, Liquidator.

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,333

    Re: OCLT and testing consistency

    It's most likely some sort of testing error. Either you didn't wait quite long enough after the last chlorine addition last night or you stopped a drop or two short last night and ran a drop or two over this morning. The lighting was different, etc..

    I'd run it again tonight and see what happens.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  3. Back To Top    #3
    BoDarville's Avatar
    Join Date
    Jun 2012
    Location
    DFW, Texas
    Posts
    3,840

    Re: OCLT and testing consistency

    Welcome to TFP!

    The most likely possibility is you are doing the evening FC test too soon after your last dose. You should give the chlorine about 30-60 minutes to circulate before testing.
    Gold Supporter, TFP Lifetime Supporter, 26,680 gal Plaster IGP 3.5 - 10' depth / Attached Waterfall Spa, Manually Chlorinated, Triton Sand Filter, 1.5 HP * 1.1 SF = 1.65 SFHP 1-speed Pentair WhisperFlo WF-26 Pump, 400K BTU NG Teledyne Laars Series One Heater, Polaris 360, Test Kit Comparison, Chlorine/CYA Chart, SLAMing Your Pool, OCLT
    A good test kit is an investment, not an expense.

  4. Back To Top    #4

    Join Date
    Jun 2013
    Location
    Central Texas
    Posts
    9

    Re: OCLT and testing consistency

    I haven't dosed since yesterday morning, so it's likely a testing error. I will try again tonight.
    15.5K gal, IG vinyl, Hayward 1/2 HP, AquaView 3.14 sq ft sand filter (above ground pool installed in ground, so no main drain), TF-100 test kit w/SpeedStir, BBB, Liquidator.

  5. Back To Top    #5
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    Location
    East Texas
    Posts
    8,995

    Re: OCLT and testing consistency

    I think you whipped the algae...beat it into submission..........and it just "threw up" the extra FC in admitting defeat! At least I hope so.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  6. Back To Top    #6

    Join Date
    Jun 2013
    Location
    Central Texas
    Posts
    9

    Re: OCLT and testing consistency

    Quote Originally Posted by woodyp
    I think you whipped the algae...beat it into submission..........and it just "threw up" the extra FC in admitting defeat! At least I hope so.
    I hope that truly is the case, but I will try again to be sure.
    15.5K gal, IG vinyl, Hayward 1/2 HP, AquaView 3.14 sq ft sand filter (above ground pool installed in ground, so no main drain), TF-100 test kit w/SpeedStir, BBB, Liquidator.

  7. Back To Top    #7

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: OCLT and testing consistency

    dspille,

    Make sure you are taking the test to it's completion....adding one last drop that does not make ANY further color change and then subtracting that drop.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  8. Back To Top    #8

    Join Date
    Jun 2013
    Location
    Central Texas
    Posts
    9

    Re: OCLT and testing consistency

    Quote Originally Posted by duraleigh
    dspille,

    Make sure you are taking the test to it's completion....adding one last drop that does not make ANY further color change and then subtracting that drop.
    I had not been doing that, but I certainly will from now on. Thanks to you all!
    15.5K gal, IG vinyl, Hayward 1/2 HP, AquaView 3.14 sq ft sand filter (above ground pool installed in ground, so no main drain), TF-100 test kit w/SpeedStir, BBB, Liquidator.

  9. Back To Top    #9

    Join Date
    Jun 2013
    Location
    Central Texas
    Posts
    9

    Re: OCLT and testing consistency

    Quote Originally Posted by duraleigh
    dspille,

    Make sure you are taking the test to it's completion....adding one last drop that does not make ANY further color change and then subtracting that drop.
    Dave,

    Does adding that one last drop impact the combined chlorine test in any way? i.e. will that extra drop prevent the test from turning pink and throw off your CC drop count?

    Dennis
    15.5K gal, IG vinyl, Hayward 1/2 HP, AquaView 3.14 sq ft sand filter (above ground pool installed in ground, so no main drain), TF-100 test kit w/SpeedStir, BBB, Liquidator.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •