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Thread: Algae Problem, High CYA & CH - Need to Drain Pool

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    Join Date
    May 2014
    Location
    San Diego, CA
    Posts
    10

    Talking Algae Problem, High CYA & CH - Need to Drain Pool

    Hello,

    I have had an algae problem for about a week now. I just got my Taylor K-2006 Test Kit yesterday. (You guys were right, pool store said they had one in stock, got there and it was a K-2005 DPD kit).

    I have been using chlorine pucks on a regular basis and Pool Time 6-in-1 shock on a weekly basis. I did not discover your forum until 4 days ago, so, when the algae started getting bad, I added, and continued to add the Pool Time shock.....WRONG, I now know!?##!?

    I had to rely on test strips up until yesterday, and they were showing my CYA level at about 150, with no FC, and a ph of about 6.8. I brought the ph up to 7.2 and have been adding 4-5 gallons of 10% liquid chlorine every evening, brushing and vacuuming a lot, and running the pump 24 hrs a day, keeping the filters clean. This has improved the algae situation.

    Now that I have the test kit, I can make better use of the pool calculator.

    Last night at 6:30 my test results were:
    FC - .6 ppm
    CC - .6 ppm
    CYA - 200'ish guesstimate (the tube markings only go to 100, the black dot disappeared after about 1/2" of water added to tube). BAD
    CH - 1100
    ph - 6.2
    TA - 100

    I added 4.5 gallons of 10% chlorine
    I did not have anything to bring the ph level up (????? is the reading even correct if I've been adding 4-5 gallons of chlorine everyday and with the current readings, below, do I need to be concerned about ph right now)?

    This morning at 6:30 my test results were:

    FC - 24ppm
    CC - .4 ppm

    Do I need to even test the ph & TA during this process?

    The algae problem is slowly improving.

    OK........so finally, here is my question:

    Obviously, I need to drain the pool. (RO is out of the question, because the two RO companies are backed up until mid-July). I live inland in San Diego and the high is about 88 degrees. If I drain the pool and re-fill it, am I at a pretty high risk of damaging the plaster? Even if I rent a pump and drain quickly, it will still take about 36 hours to refill.

    I read in one of the other threads something about "draining from bottom and adding water to top". ?????????

    Any advice from you wonderful pros would be greatly appreciated.
    Appx 11,000 gallon in ground plaster pool with spa. Sta-rite System 3 Filtration System, 300 sq ft cartridge filter. Max-E-Glas 1.5 hp pump, Baracuda G3 automatic pool cleaner.

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    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Algae Problem, High CYA & CH - Need to Drain Pool

    You can drain and fill at the same time. It will require more water to get the levels down an appropriate amount that way, but typically not too much extra water.

    Generally you want to fill on the bottom and drain from the top. Fill water is typically colder and will sink to the bottom. If your fill water is warmer than the pool you do it the other way around. If you do this while the main pump is either off or draining to waste, the amount of mixing that goes on in the pool will be minimized and you will use less extra water.

    Fighting algae when CYA is around 200 is fairly hopeless. I recommend waiting on adding more chlorine until you get your CYA level down to something more reasonable.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  3. Back To Top    #3

    Join Date
    May 2014
    Location
    San Diego, CA
    Posts
    10

    Re: Algae Problem, High CYA & CH - Need to Drain Pool

    Thanks for the quick response.

    Do you know how long the plaster can be exposed before it starts getting damaged? My pool is 16 years old and (in my non-expert opinion),
    the plaster is not in that good of shape to start with. The temps do start cooling down around 5pm and the pool is shaded by about 4pm. If we started draining with a fast pump and refilling that evening, it would leave part of the pool exposed the following day. Is this amount of time trouble in regards to plaster?

    I'm not sure how much temperature difference there is between our fill water and pool water. I'll investigate that. Water out of the hose is pretty warm this time of the year.

    Thanks again!!!
    Appx 11,000 gallon in ground plaster pool with spa. Sta-rite System 3 Filtration System, 300 sq ft cartridge filter. Max-E-Glas 1.5 hp pump, Baracuda G3 automatic pool cleaner.

  4. Back To Top    #4

    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    282

    Re: Algae Problem, High CYA & CH - Need to Drain Pool

    Just out of curiosity, how does the CYA get up that high?

    I was under the impression that low CYA was the common problem
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

  5. Back To Top    #5

    Join Date
    May 2014
    Location
    San Diego, CA
    Posts
    10

    Re: Algae Problem, High CYA & CH - Need to Drain Pool

    Honestly, I am not sure, but here is my best guess:

    We have used Pool Time 6-in-1 shock and chlorine tablets for 10 years. Both have stabilizers in them. When my algae problem came along, I added a couple bags of the shock, and added a couple more bags a few days later. I did accidentally add 1 cup of stabilizer (thinking it was ph up), but that is the only time I have ever purchased or added stabilizer. I haven't ever drained my water, and I've lived here for 10 years. Water is pretty scarce in this part of the country.

    If that doesn't explain it, then I'll just say "It's all my husband's fault".
    Appx 11,000 gallon in ground plaster pool with spa. Sta-rite System 3 Filtration System, 300 sq ft cartridge filter. Max-E-Glas 1.5 hp pump, Baracuda G3 automatic pool cleaner.

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