Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 12 of 12

Thread: CYA test off the chart

  1. Back To Top    #1
    surfhawaii's Avatar
    Join Date
    May 2011
    Location
    Kailua, Hawaii
    Posts
    61

    CYA test off the chart

    Hi...my first post, thanking responses in advance.

    From Taylor kit test my CYA level doesn't even come close to 100 mark which, since scale is inverted, I'm assuming it means it's around 200 or so. Tested twice, same result. From what I've read here the only way to lower this is to drain and refill. Question is, how much to drain? I know the answer will probably be 'it depends' but for a ballpark, is that 1/10 of the pool, 1/4, etc.

    Other test results show pool needs some chemicals (need to raise ph, etc.) but if I'm going to be draining/refilling, doesn't make sense to try to work on other stuff until I get CYA under control because I would be losing new chemicals anyway, correct?

    Thanks.
    24.5k gallon
    Sand filter (Triton II TR 100)
    IG tile
    Pentair VS+SVRS pump
    Sundance Chelsee spa

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,090

    Re: CYA test off the chart

    Welcome to TFP!

    Unfortunately, that probably means about half the water. You can get a ballpark idea of where your CYA really is by using twice as much water and doubling the reading. It's not highly accurate, but will give you an idea.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: CYA test off the chart

    The "simple" answer is ... depends on what level you want

    If you replace 50% of the water, your level with drop by 50%. If you replace 75% of the water, your level will drop by 75%.

    This assumes you do it all at once. If you do smaller drain and fills, it will take more water replacement to get to the level you desire.

    If you are at 200 (not really easy to determine), I would guess you should replace 75% of the water to get close to 50 and then retest and adjust again as needed.

    ETA: I would think you would be best getting the CYA level correct through water change(s) before adding a "bunch or other stuff". Although you should maintain enough FC so that algae does not start to grow in the process.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  4. Back To Top    #4
    surfhawaii's Avatar
    Join Date
    May 2011
    Location
    Kailua, Hawaii
    Posts
    61

    Re: CYA test off the chart

    Thanks for prompt response but, was afraid you'd say this. Next question is since I'm a newbie to this, what is most efficient way to do this, run the pump while refilling with water (seems this would lose some of the new water I was putting in), get a pump to empty it, etc.? And, just curious, assuming this didn't happen overnight (or does it?) since I just took over maintaining pool from pool service, shouldn't they have been testing/moderating CYA?
    24.5k gallon
    Sand filter (Triton II TR 100)
    IG tile
    Pentair VS+SVRS pump
    Sundance Chelsee spa

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: CYA test off the chart

    There is relatively low awareness in the industry of the problems of high CYA levels.

    You need to replace water to get CYA down. The quickest way to do that is to run the pump on backwash while filling from a garden hose. The pump will probably pump out faster than the garden hose will fill, so you probably need to turn the pump on and off occasionally to keep the water level from getting below the skimmer. This is not perfectly efficient, but it is very easy. To be more efficient, you need to pump the water level down several feet and then refill, which that can be tricky unless you have a main drain and can turn off the skimmers.
    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

  6. Back To Top    #6
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: CYA test off the chart

    I currently have a "pool" company and I am pretty sure my CYA is up at your levels ... they think it is adequate to come by once every 2 weeks and pump some gas in the pool. So the FC goes sky high and then drops for 2 weeks ... thus they need the high CYA I guess. I too am getting ready to oust them and take over, probably with a SWG, so I will also have to change over 50% of my water.

    Regarding the water change, ideally you do not want to be adding while you are removing and the addition will dilute what you are removing resulting in more water change required. If you can isolate you main drain, I guess you could use that to empty. I have in the past rented submersible pumps from Home Depot (not sure that is an option for you).

    NOTE: care need to be taken when draining the pool. If the ground water table is high, your in ground pool (although I guess I assumed that) could pop out of the ground. That is why some people recommend multiple smaller water exchanges (also required if you have a liner pool I guess).

    A side conversation on jblauert's issues has been moved to this topic. JasonLion
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  7. Back To Top    #7
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: CYA test off the chart

    How to best do a water exchange depends on a number of factors, type of pool, water table (can you drain at once without having to worry about your pool floating up), etc. If your fill water is colder than the pool water (often the case with private wells in the summer in most areas) the fill water will tend to sink to the bottom, so if you drain from the surface while filling cold water at the bottom and not circulate the water it will tend not to blend as fast.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  8. Back To Top    #8

    Join Date
    Jun 2010
    Location
    San Antonio
    Posts
    424

    Re: CYA test off the chart

    I do not have a main drain so when I was faced with having to drain a couple of feet of water I put a hose a vacuum hose into the pipe leading from my skimmer to the pump and pumped to waist. If you are not worried about draining too much water at a time the same technique might work for you.
    Larry in Texas

    Above ground 7,700 gallons, 19 inch sand filter ( 2 sq. ft.), Liquidator, and a WaterWay Hi-Flo Pump with an A.O. Smith 1 hp SF 1.0 motor.

  9. Back To Top    #9
    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Location
    Houston, Texas
    Posts
    9,202

    Re: CYA test off the chart

    Back to the original question! Surfhawaii, you may need to drain more than once to get the CYA level where you need it to be. Also, you need to decide how you will chlorinate the pool in the future. Do you plan to continue using liquid chlorine, or do you plan to add a saltwater chlorine generator? If you choose the swg, then you will keep the CYA around 70-80 ppm. For liquid chlorine you will drop down to 30-50 ppm.

    You could use the manual vacuum set up and filter set to waste to pump water out of the pool. Set the vacuum head in the deepest part of the pool. Drain about 1/2 the water and refill. Circulate the water for an hour or two then test CYA to see if you need to drain any more water.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
    Love TFP? Become a
    TFP Supporter!

  10. Back To Top    #10
    surfhawaii's Avatar
    Join Date
    May 2011
    Location
    Kailua, Hawaii
    Posts
    61

    Re: CYA test off the chart

    Thanks for all the replies, I need these discussions because I'm new at this. Went to local pool place and had them perform test just to make sure I was doing it correctly and they got same results and said same thing as you guys...drain the pool. They rent submersible pumps and they're recommendation was to just drain the whole thing because concentration was so high. Although I'll have to pay for water, might be just as easy with strong pump.

    They also recommend using chlorine tabs that are 99% chlorine instead of the ones I'm using (pooltime) that also have a stabilizer in them. They also recommend doing test for phosphate. So, questions for you experts:
    Agree with 99% chroline tabs?
    Agree I need to do phosphate testing?
    And, do you have recommendations on what chemicals I should add once water has been totally replaced?

    Thanks again.
    24.5k gallon
    Sand filter (Triton II TR 100)
    IG tile
    Pentair VS+SVRS pump
    Sundance Chelsee spa

  11. Back To Top    #11
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,349

    Re: CYA test off the chart

    Here's my thoughts.
    1) If it's a tablet is has either CYA, calcium, or lithium in it. I'm not sure what they're recommending but it's going to add one of those if it's in tablet form. Find out which and post back.
    2) Don't waste your time on testing for phosphates. If they test for it they're going to try and sell you something to correct it, when in reality it's irrelevent. Maintaining proper FC levels will keep algae from starting at all, and you have to have that for a sanitary pool anyway.
    3) You need to test the water (or the fill water) and use the Pool Calc to figure out how much you need of what. The only sure thing you're gonna need is chlorine.
    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

  12. Back To Top    #12
    bobodaclown's Avatar
    Join Date
    Apr 2011
    Location
    Lakeland, FL
    Posts
    2,351

    Re: CYA test off the chart

    I bought a $100 sump pump from HD and some hose to drain my pool. I've got a cartridge filter and it only has a 5/8 drain on the top. Worked well. Change about 1/2 the water to get approx CYA=100.
    17K Kidney Shaped Pool Concrete (Diamond Bright) Pool, 3/4 hp 2 speed 115V Sta-rite Duraglas PEA5D-180L/P2R5D-181L (Impeller C105-92PS Diffuser C1-216P), 1.5 piping, Pentair CC100 Filter , Heat Siphon 100K BTU Heat Pump Pool Heater, Flow meter Blue White Flowmeter Model No. F-30150P, Hayward Astrolight SP0581N, SWCG CalimarTitanium Edition TE45 , Dolphin Nautilus Plus with CleverClean, Lakeland Florida

Posting Permissions

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