Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 3 of 3

Thread: Test results after partial drain and refill

  1. Back To Top    #1

    Join Date
    Jun 2007
    SF Bay Area

    Test results after partial drain and refill

    I had pump problems between October 2007 until early May 2008. I had clear water all through this timeframe by adding a gallon or two of 10% liquid chlorine as appropriate for the 100-150 ppm level of CYA. Only when the water temperature reached 60-65 and above in mid-to-late April did I start having problems. Before I knew what hit me, I had quite the algae bloom.

    I did a two-pronged approach. I hit the mess with 40-50 PPM chlorine while performing a partial drain and refill. The draining portion ended up taking 3 days or so, for a variety of reasons. I ended up replacing 10,500 gallons of my 23,500 gallon pool, which is about a 45% water replacement, which is great since I was aiming for between a 1/3 and 1/2 drain and refill. The draining process ended at 9PM on Friday, and the refill process took from then until around 1 PM today (Saturday).

    The rest of the day involved a continual clean-out of the Polaris 380, which must have happened at least 12 times. The wireless remote (part of the GoldLine/Hayward AquaLogic automaton system) saved quite a bit of time as I could turn off the Polaris cleaner right at poolside, clean out the sock, toss the Polaris back in the water, and turn it back on via the wireless remote, all without having to continually trudge to and from the equipment pad. The algae had turned into fluffy white deposits on the bottom of the pool, which tended to clump together as white strings in the Polaris or in the skimmer basket. The pool is now back to its normal crystal clear state.

    The new test numbers taken tonight are as follows:

    FC - 16.0 (residual effect of the above-mentioned shocking)
    CC - 0,.5
    pH - 7.5-7.8 (I realize this number may be off because of the high FC, not to mention I am terrible at color comparisons)
    Alk - 80 (was 110 or 120 when tested last summer)
    Cal - 170 (this confuses me - my calcium numbers last summer were on the order of 400. The 170 number does not jibe with the previous test result of 400 and my replacement of less than 1/2 the water volume)
    CYA - 60-70 (this was read indoors, so I am hoping that an outdoor test tomorrow will show an even lower number. In any case, still a huge improvement over my inherited 100-150 ppm of CYA)
    Temp - 71 deg. F.

    I think all of my numbers look pretty good, except perhaps for the Calciium reading. Any thoughts or comments?


    24,000 gallon inground freeform pool/spa circa 1983 (113 ft perimeter, 625 sq ft) with 350 gallon attached spill-over spa
    2007 2 HP, three-phase Hayward TriStar pump which is powered by an Ikeric VS-200 variable speed drive system
    1983 Laars XE Pool/Spa Heater Type ES 400,000 BTU, 1998 Hayward Super Star-Clear C-4000 cartridge filter (400 sq ft, 4 separate cartridges)
    1998 Polaris 380 pressure-side cleaner w/ 3/4 HP booster pump
    One skimmer :( and one PoolSkim :), One Supervision Galaxy LED pool lamp, Second story solar panels
    Hayward/GoldLine AquaLogic PS4 (replaced 1983 vintage dual circuit Intermatic timer)

  2. Back To Top    #2
    Butterfly's Avatar
    Join Date
    May 2007
    South Carolina
    Yep, Great Job!

    As you already said, verify your #'s when the Cl drops and adjust.

    You are on your way to a very happy swim season
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida
    How does your water look? Clear?
    Are you able to maintain a steady FC overnight?

    If the answer to the above in "excellent" and "yes", you are virtually done.

    You will find the lower cYA...even if it's 70, to be far more manageable than before and you will mostlikely not have any future algae problems.

    Your apparent loss of calcium is puzzling because typically it doesn't go anywhere. What is the CH content of your fill water? That may explain some of it. Secondly, I would get a pool store test. If it matches up on CH then you can add a little bit (I would keep it under 300ppm but more than 200.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

Posting Permissions

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