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Thread: CYA problem

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    pikeman's Avatar
    Join Date
    Jul 2008
    Pflugerville, Texas

    CYA problem

    I had to hire a pool service for about a year due to job travel. They used triclor pucks in a floater. I recently quit my job and fired the pool service when the guy said he'd have to drain my pool due to the CYA getting up to 100. It was time to get back to doing it myself (BBB method).
    I double-checked the readings, and it was actually 100. It was as clear as a dew drop without any algae. We use a polyquat algaecide. (I have a Nautilus 48 DE filter and backwash every two weeks.) FC was about 2.0, but of course ineffective due to the CYA load.
    I was not going to buy the snake-oil chemical treatment, so drained the pool as much as possible. The pump quit pulling with about a foot of water left over the drain, which was pretty good considering the challenge of pushing the water up a shallow slope for 100'. I was at least 80% drained.
    I refilled and to my horror, the CYA is 80! I had it checked at the pool store and repeated the test. I'm using the TF100 kit.

    The pool is a ~15K gallon in-ground lined with Wet-Edge Tech Prism Matrix two years old, if that could have anything to do with it??? All I can say is $%^$#!!!
    I'm really reluctant to drain it again with my pump. If I have to drain it AGAIN I'd hire a pool company to drain it completely dry.
    Is that what I am faced with? Not to mention a heck of a water bill.
    20K IG, WetEdge technology lined pool, TF100 Test Kit, CircuPool RJ60+, StaRite pump, Hayward DE filter, Hayward Navigator pool vac. Zodiac MX8 vacuum thrown in garbage.

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    Mod Squad Jimrahbe's Avatar
    Join Date
    Jul 2014
    Bedford, TX

    Re: CYA problem


    Not sure of your water rate, but here in Bedford I can fill my 17K pool for $50 bucks. If you tell the city they don't charge the associated sewer fee..

    100 is the max the CYA test can see, so it could easily have been much higher than 100 ppm.

    I never recommend using the pool pump to drain a pool. I suggest you buy or rent a submersible pump. Or your can just stick a garden hose in and run the other end down hill.. a little suction and you can siphon the water out. Takes longer but it is free..

    Thanks for posting,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

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    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Cartersville Ga

    Re: CYA problem


    If your pool is clear and algae free. 80 CYA is manageable. Not recommended, but manageable. Just make sure to maintain your FC at the proper level according to the FC/CYA table.

    Here is a link to it. Pool School - Chlorine / CYA Chart
    Bob - INTEX 12x24 owner (not setup yet), 'New to me' Kreepy Krauly Sand Shark, Test kit: TF-100 w/Speed Stir

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    Join Date
    Sep 2016
    Tucson, AZ

    Re: CYA problem

    My experience is that you have to be very careful with CYA measurements. The test kit that the pool store uses (and that I use now) only measures up to ~100ppm; anything over that still gets reported as 100ppm. I was in the same situation last year; the pool store said my CYA was 100 but I was completely chlorine locked so I ended up buying a Taylor kit, doing a 1-3 dilution of the pool water and, lo and behold, the CYA tested 80, meaning the original concentration was 320!
    I rented a pump from Home Depot, drained and refilled the pool, and now only add CYA to 40ppm, then BBB all the way.

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    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: CYA problem

    pikeman, the math on CYA drains is quite simple. If you drain 50 % of your pool, the CYA reduces by 50%.

    If you drain 50% of your remaining water, your CYA will come down to 40 ppm. easy peasy.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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