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Thread: Community Pool Experiment - Why no Algae?

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    Community Pool Experiment - Why no Algae?

    As described in my intro post, I don't own a pool but I live across the street from our outdoor community pool. Since I service three SWG pools as part of my home care-taking business, I have been interested in how the pool service company is maintaining the community non-SWG pool. I have raised some issues with the HOA board about the chemical imbalances the pool company has allowed to occur using the knowledge I have gained on this great forum.

    Using the Taylor K-2006 kit I use in my other pools, my first test saw the black dot for CYA disappear at about one-half inch of solution, or far above the 100ppm gradations.



    The FC came in at 35 ppm. I did more tests in the days that followed and obtained the same result for CYA and similar results for FC. My R-0013 for CYA, R-0870 and R-0871 for FC were less than one-month old, so I discarded doubt about their efficacy.

    Since the FC was so high, I knew from reading this forum that the pH test is useless, so I ignored that.

    I then notified the HOA chairman about this imbalance. Since it was so out of whack, she contacted the pool company who promptly took a sample to Leslie's Swimming Pool Toy Store for a test. Their result for FC at 5 ppm and CYA at 120 ppm.

    Feeling confident, the pool company then asked for a test from the Santa Cruz County Health Department (SCC).

    Feeling curious, I met with the SCC tester at the pool to observe his "tests." He was a very pleasant Mexican gentleman who kept nodding in agreement when I told him that the CYA was too high and that the pool company was trying to compensate by maintaining the chlorine at a very high level with chlorine pucks, which was raising the CYA even more.

    He calmly took out his Walmart HTH test kit and dipped the tube into the water just enough to fill it. Dropping the obligatory five drops of OTO into the tube, he capped and shook the container, eyed the result and commented, "It looks good 3ppm."

    Trying not to chuckle, I pointed out to him how much darker yellow the test sample was than the 3ppm indicator.

    "Yes, you are right. It is darker."

    He logged the FC in at 5 ppm, then took the useless pH test which read 7.4. There was no CYA or any other test. He said he would be back to check the chlorine and pH again to see if the pool company brings the FC back down to the "accepted" level. of 3ppm.

    The pool company let the FC drop down to 10 ppm. The health department gentleman returned and, when the HTH kit read over 3 ppm FC level, he switched to an "old" kit which magically gave him the 3 ppm level he sought.

    The pool passed with flying colors.

    Since then, using the information I learned from this board, I used the dilution method of testing for high CYA and obtained a reading of 400-500 ppm. I had to use 6 parts tap water and 1 part pool water to get a reading of 55 ppm on the scale. I then multiplied the result by 8, allowing for dilution error.

    The chlorine level has fluctuated between 0 ppm and 22 ppm.

    One of my pools developed yellow algae in the spa within one week after the SWG went belly-up dropping the FC to zero in the hot Arizona sun. Yet, after over two months of sky-high CYA and insufficient FC, there is still no sign of algae in the community pool; and my tests find no Combined Chlorine present.

    So, how is this pool defying the laws of chemistry put forth on this forum? The pool company could be using algaecide I suppose. I did see a bottle of water clarifier next to the pool pump.

    Today I tested the water at FC 8.5 ppm and CYA at 425-525 ppm and the pool looked crystal clear.


    Edit: Use URL for photo
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    JoyfulNoise's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Based on chem geek's advanced pool chemistry thread, an FC of 8.5 and a CYA 425 would yield the following active chlorine (hypochlorous acid) level -

    [HOCl] = 8.5ppm / (2.7*425ppm - 4.9*8.5ppm +5) = 0.007ppm

    That puts the active chlorine well below the kill rate threshold for bacteria and very far below the kill rate of algae. Just try to remember this - clear water IS NOT a sign of sanitary water.

    As you mention, they may use heavy doses of chlorine (shock) and algaecides. They may have even used phosphate reducers to lower the phosphate levels in the water. They may also do regular water exchanges and/or use clarifiers to help coagulate and trap particulates. All of those things can make water look clear. The problem is, if anyone swimming in that water has a communicable disease, the risk of person-to-person disease transmission is very high. I would certainly not swim in water like that.

    Perhaps you might print off some of the materials in chem geek's advanced chemistry section and show it to your HOA president. Let her know that the CYA is excessively high based on your testing and show her the thresholds for pathogen CT kill times. The Health Dept probably only has to check pH and FC by regulation. Therefore they are not going to be aware of the more complex issues. It sounds like that fellow who tested water was simply going through the motions and using a very basic OTO chlorine test. Very sad indeed.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Divin Dave's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Stoney,
    you need to understand, that the pool industry and health department do NOT recognize the FC/CYA ratio.
    They likely never will, because doing so will not result in higher sales of their chemicals. Thats all there is to it.

    The pool industry folks who maintain swimming pools commercially are in most localities, required to attend
    Certified Pool Operators class and get their certificate. What is taught in that class is all they know and is what they go by.
    What is Not taught in that class is what we go by.

    As for why not algae,
    They likely are using algaecide and phosphate removers and shocking weekly.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    Re: Community Pool Experiment - Why no Algae?

    Unless they are using a lot of algaecide, you could throw some (mostly phosphate) fertilizer in that pool and see the algae develop. The other thing that can happen is when the bather load is high enough to have a lot of monochloramine in the pool (that shows up as CC) since that kills algae and is not moderated in its strength by CYA.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Community Pool Experiment - Why no Algae?

    Thanks for the very interesting replies. I am sending the HOA chairman a link to this topic.

    It is fortunate that this pool is rarely used.

    The HOA is firing the pool service company. They want to hire me to take care of the pool but that hasn't been finalized. I have suggested installing a SWG to facilitate a more steady chemical balance without the mess/storage of liquid chlorine or bleach.

    They have agreed to drain the pool to replace the water. I have volunteered to set up and monitor the operation. Since the pool is one-quarter mile from the Santa Cruz River, I plan to drain/refill one-third of the pool at a time using a submersible pump connected to the sewer.

    I am open to any suggestions you people may have regarding this operation.

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    JoyfulNoise's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    I forgot, are you a Certified Pool Operator (CPO)? If not, you may need to check local regulations on the issues. Some jurisdictions (maybe even most of them) require that any public/commercial pool has a CPO managing it. It may also matter for insurance purposes as well. What you have there certainly qualifies as a "public" pool in my mind so you want to make sure you dot your "i's" and cross your "t's" when it comes to following regulations. The last thing you want is your local health board shutting down your pool, or worse, levying fines.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Community Pool Experiment - Why no Algae?

    Santa Cruz County is a time-warp back to the 1950's. There are no requirements for pool service operators.

    However, the HOA does require liability insurance. They are dotting my "i's" and crossing my "t's" for me.

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    Mod Squad kimkats's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Stoney that is SO neat they are listening to you! Now do something for you, us, and them............do a full set of tests AND take several pics of the pool in full sun. Looking down at the steps, across the pool, down at the deep end, shallow end, etc. Make sure there is a date stamp on the pics.

    Once you take over the pool and get all of the levels balanced take the pics again. I am betting there will be a big difference in the pics. More sparkle and shine!

    Good luck!

    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: Community Pool Experiment - Why no Algae?

    As kimkats requested, here are the before-after shots of our HOA swimming pool. The pool boys did their best with loads of clarifiers and Fiber Clear in the skimmers but the 500+ CYA finally took its toll.





    Nothing left to do but change the water. Multiple members told me the pool had been emptied and acid-washed two years ago. That eased my concern that the pool would float like a big concrete schooner.



    After filling the pool and balancing the chemicals I am working to bring down the high tap water alkalinity (220ppm) by aerating to raise pH and adding small quantities of muriatic acid daily. Little-by-little the TA is now down to 140ppm adjusted for CYA. I plan to increase borates when it arrives at a good level.



    I stuck 1/2" irrigation drip line into the return jets to create little fountains for aeration. The HOA members think they're cute.



    They also love the "sparkling water."

    Thanks TFP!

    .

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    JoyfulNoise's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    If you use pool math, do not adjust the TA value for CYA or else you will get inaccurate results. PoolMath already does the adjustments internally. Just use whatever the TA value is from the test drops.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Community Pool Experiment - Why no Algae?

    Thanks JoyfulNoise. That's good to know.

    I have been using Pool Math but adding less than the quantities suggested and testing daily.

  12. Back To Top    #12
    JoyfulNoise's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Pool looks AWESOME!

    I have to ask - was there anyone in your HOA that was against having you take over the pool maintenance? If so, they're eating crow right now looking at that water.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Community Pool Experiment - Why no Algae?

    So are you totally the "pool guy" for the neighbohood pool now? No more Mumbo-jumbo?

    - - - Updated - - -

    And wait on those borates until everything is REALLY stable.

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    Re: Community Pool Experiment - Why no Algae?

    + JoyfulNoise — Nobody protested against me taking over. I do handyman work for many of them and they appreciate attention to detail.

    + MarianParoo — Yes. I'm the pool guy. I'm also looking for ways to save the HOA money. The pumps have been running 24/7 so I'm trying to convince them how wasteful it is.

  15. Back To Top    #15

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    Re: Community Pool Experiment - Why no Algae?

    Right now, you need the pump on for aeration to lower that TA!

    Also, people will flock to the pool now that it is inviting!

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    Mod Squad kimkats's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Well done!

    Did anyone swim in it when it was like the before picture? That is SCARY!

    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: Community Pool Experiment - Why no Algae?

    + MarianParoo - There were three people in the pool today. In this little village three is a "flock."

    + kimkats - One woman did go swimming in that water. She said, "The Great Lakes look like this and they're okay to swim in."

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    JoyfulNoise's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    I noticed in that pic with the drained pool you had a pretty serious case of calcium scale on your water line tiles. They must have taken a beating over the years from the "excellent" pool service your HOA was using.

    PM me if you want the name of a company (in Phoenix) that does soda blasting to remove calcium. I had my tile work done about 2 years ago and they did an incredible job. And all you have to do is drain the pool to below the tile line (a few inches of water) and the guy will jump in the pool and blast away. The media is perfectly on tile glaze and grout lines. My pool tile looked brand new when when they finished.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Community Pool Experiment - Why no Algae?

    Thanks JoyfulNoise. I'd be glad to have that information. A lot of pools down here could use it due to the high calcium hardness in the water.

  20. Back To Top    #20
    Mod Squad kimkats's Avatar
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    Re: Community Pool Experiment - Why no Algae?

    Is there no oversight for public pools? It seems as if that pool should have been closed due to be unsafe if for not other reason than a person could not been seen under the water! Scary! Thank goodness they have you!

    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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