Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 9 of 9

Thread: Normal range of hypochlorite use??

  1. Back To Top    #1

    Join Date
    May 2013
    Location
    Dallas, TX
    Posts
    66

    Normal range of hypochlorite use??

    I have a 25,000 gal in ground plaster pool, CYA = 45-50, CA = 270. Totl AL = 70 pH = 7.5. I went through a shock and it finally stabilized at 22.5 ppm overnight. Then, the next day the FC plummeted to 12 during the day. Today it fell to 3 even after adding 2 quarts of bleach (8.25%).

    This seems to be a large amount of chlorine usage. What is the normal chlorine usage for a pool this size in the summer????
    In-ground plaster pool, ~18,500 gal, Hayward single-speed pump, Pentair 60 sq. ft. DE filter, Polaris 280 robotic cleaner, SPA, heater (seldom used), use Taylor K2006 series test kit

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Normal range of hypochlorite use??

    Well, we usually say 2-3ppm loss each day is "normal" ... but that is not true if you are starting at shock levels (in reality you lose a % of the FC every day) ... and every pool is different.

    Your use sounds high ... much like I am seeing. With a CYA around 45ppm I am seeing around 5-6 ppm lose each day ... I have a LOT of sun down here so working to raise the CYA a bit more to see if that helps. If you pass the OCLT, that means that most of your losses are sun related.

    From Pool School:
    If you don't have a SWG or problems from extremely high amounts of sunlight, CYA is typically kept between 30 and 50. If you have a SWG or very high levels of direct sunlight, CYA is typically kept between 70 and 80.
    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!

  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Normal range of hypochlorite use??

    Chlorine usage is a percentage of your starting level. With CYA a little under 50 you can expect somewhere in the range of 30% to 50% chlorine loss per sunny day in most places, perhaps a bit more or less in more extreme situations.

    Once everything is balanced and you are using normal FC levels you can expect to use 2 to 3 ppm of chlorine per day, though again that varies from pool to pool.
    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

  4. Back To Top    #4

    Join Date
    May 2013
    Location
    Dallas, TX
    Posts
    66

    Re: Normal range of hypochlorite use??

    I should be running close to 4 ppm with a CYA of close to 50. If I lose 50% each day and must replace, it will cost me about $54 per month just in chlorine costs, according to the numbers I am getting from the pool calculator. (I can buy 3 119 oz jugs of 8.5% chlorine at a big box store for $8.50, and if my arithmetic is correct, that comes out to 2.38 cents per oz.). That seems high. But, I don't believe the pool calculator. When I shocked from 0 ppm, I put the calculated amount in the pool to give me 20 ppm. I actually got 33 ppm, so something is wrong. Either my pool is not 25,000 gallons as I was told, or something is wacko.

    I just had to pay for almost a whole pool of water because my CYA was too high. That's the second dump in 6 months, so I leery of adding trichlor or dichlor to up the CYA. Anyway, that will increase the amount of chlorine I have to add to the pool to be effective. There must be a discussion about this somewhere on the forum.

    I may just experiment with putting in measured trial amounts of bleach and see what levels I get in the pool. I suppose there is a way to back calculate the pool volume doing this.
    In-ground plaster pool, ~18,500 gal, Hayward single-speed pump, Pentair 60 sq. ft. DE filter, Polaris 280 robotic cleaner, SPA, heater (seldom used), use Taylor K2006 series test kit

  5. Back To Top    #5
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,965

    Re: Normal range of hypochlorite use??

    If your FC held overnight for multiple nights, I would suggest trying a slightly higher CYA of 60-70. I know this bucks tradition but if it's clear and you test diligently you can absolutely run with a higher CYA to protect the FC - just don't EVER get lax AND NEVER let the FC drop below your MIN level. EVER.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  6. Back To Top    #6

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,084

    Re: Normal range of hypochlorite use??

    But, I don't believe the pool calculator.
    Well, it works for thousands of us. What's not to believe?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  7. Back To Top    #7
    BoDarville's Avatar
    Join Date
    Jun 2012
    Location
    DFW, Texas
    Posts
    3,840

    Re: Normal range of hypochlorite use??

    But, I don't believe the pool calculator...Either my pool is not 25,000 gallons as I was told...
    I believe it's the latter. Pool calculator is spot-on for my pool and seems to be that way for many thousands of us, as duraleigh stated.

    I would re-measure the pool volume. There is a tool at the bottom of the pool calculator for measuring pool volume, or you can try this link: Pool Volume Calculator

    Other things to check that can contribute to FC consumption include making sure your skimmer baskets and pump strainer are clear of any organic debris. You pool could be spotless, but if there's lots of organic material hiding out in these places, it's still in the system and will result in constant parasitic FC consumption. Same thing goes if you have a pool vac and leave it in the water much of the time. If so, you should clean out the vacuum bag after every or every other use, depending on how much material is in the bag.
    Gold Supporter, TFP Lifetime Supporter, 26,680 gal Plaster IGP 3.5 - 10' depth / Attached Waterfall Spa, Manually Chlorinated, Triton Sand Filter, 1.5 HP * 1.1 SF = 1.65 SFHP 1-speed Pentair WhisperFlo WF-26 Pump, 400K BTU NG Teledyne Laars Series One Heater, Polaris 360, Test Kit Comparison, Chlorine/CYA Chart, SLAMing Your Pool, OCLT
    A good test kit is an investment, not an expense.

  8. Back To Top    #8

    Join Date
    May 2013
    Location
    Dallas, TX
    Posts
    66

    Re: Normal range of hypochlorite use??

    I measured the pool and it comes in closer to 18,500 gallons not counting the spa, but it's a very rough estimate. My pool is difficult to measure due to its varying dimensions.

    There should be a way to do a "dye dilution" test on a pool and get its exact volume, i.e., you put a known quantity of concentrated something in the pool and once it is distributed you measure its concentration. Does someone know how to do this? Measuring a pool's dimensions is subject to big errors due to rounding of the bottom, irregular pool shape, steps in the pool, etc. Also, spa volume.

    I should also add that this pool is in Texas, it gets a LOT of sun, and the wind blows fiercely and constantly here, blowing dust and debris into the pool on a regular basis.
    In-ground plaster pool, ~18,500 gal, Hayward single-speed pump, Pentair 60 sq. ft. DE filter, Polaris 280 robotic cleaner, SPA, heater (seldom used), use Taylor K2006 series test kit

  9. Back To Top    #9
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Normal range of hypochlorite use??

    Trust the pool calculator and eventually you will get a better idea of the volume. If you consistently are below or above your targets then you should adjust your volume. It is not that important to be exact.
    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!

Posting Permissions

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