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Thread: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

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    Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    I have an 18'x36' inground kidney shaped pool (22,500 gallons). Towards the end of last summer the water looked good but I had no chlorine reading. I assumed my 7 year old swg system met the end of its life. I now just opened the pool and fully replaced the swg system. The water looks perfect but I still can't get a chlorine reading regardless of whether I run the swg at 100% or if I dump 2 pounds of shock in. Water test results: chlorine 0, ph 7.2, alkalinity 50, calcium hardness 140, cya 75, phosphates 100ppm, nitrates 30ppm.

    I didnt bother adjusting the alkalinity or calcium hardness yet because the pool store told me to drain and refill due to nitrates. Since learning that nitrates usually come from fertilizer, I noticed that my lawn company uses a rotary spreader that shoots out the fertilizer. In fact there is usually fertilizer on the pool deck after they come. I imagine that's how I got the nitrates. Needless to say I will discontinue with the lawn company.

    My pool install company said to drain half the pool and refill? Any thoughts?

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Welcome to the forum. .

    The first thing to understand is you CAN get a chlorine reading, you just haven't put enough in yet.

    Phosphates and nitrates have nothing to do with your issue. Something (perhaps ammonia) is consuming your FC as fast as you put it in.

    So, put in a calculated amount of FC using the PoolMath feature we have. Let's assume you calculate that one jug of chlorine will raise FC by 4 ppm.

    Put that amount of chlorine in and wait 10 minutes and then test again. If the chlorine goes back to zero, then you have ammonia and you put in another jug (and another and another, and another)

    At some point, you will have added enough chlorine to burn off the ammonia and you can get to work balancing your pool.

    Please consider purchasing one of the suggested test kits. To really manage your pool, you have to do your own testing......don't rely on the pool store to look out for you.......they won't.

    Read "The ABC's of Pool Water Chemistry" up in Pool School. It's the right place to start.
    Dave S.
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    Mod Squad pooldv's Avatar
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Welcome to TFP!

    I definitely recommend getting a great test kit. I have used the TF100 from TFTestkits.net for many years and gladly recommend it.

    +1 to phosphate and nitrate not being the problem with your pool. My pool has been clear for 4 years and never drained and I have never even tested for phosphate or nitrate.
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    So I am looking into your idea because the thought of draining the entire pool is not even realistic. Apparently I would destroy my vinyl liner even if I tried. I may lower the water 1 foot, refill, and then repeat that process a few times. At a minimum it should at least lower the nitrate level. Then I will pour in a jug of liquid chlorine and retest. Might be the best option...

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    At a minimum it should at least lower the nitrate level.
    Nitrates are not relevant.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Hearing that really makes me feel better.

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    Mod Squad pooldv's Avatar
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    For future reference if you ever do decide to drain your pool leave a foot of water in the shallow end.
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    I've been looking at the pool math calculator... What type of liquid chlorine would you recommend? I don't want to damage my liner or raise my CYA level which is presently at 75-80. My hardness is presently low at 140 so that's no big deal if it goes up.

    Thanks again!

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Any liquid chlorine(bleach) will be fine. Just put it's % in pool math and it will tell you how much to use. Lately, Walmart has been running a special on 10% in the pool area. 2/$5.00 No issue with liner or CYA when using liquid chlorine(bleach) that's why we suggest it.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    So here is an update: I did not drain the pool at all. I turned off my SWG and added 12% liquid chlorine and raised my chlorine level to 10ppm. The chlorine held reasonably and took a few days to drop to under 5ppm. I then had to raise my alkalinity and calcium hardness (not on the same day). I re-tested my water and got the following results: Chlorine 4, PH 7.6, Alkalinity 110, Calcium Hardness 250, CYA 75. I then took a water sample to the pool store and had them test for nitrates and phosphates. Nitrates came back at 10 or less, phosphates came back at 100 or less.

    So now, the only thing I am "watching" is the chlorine level. I turned back on my brand new American SPS Resilience A5 Salt Water System, set it to 50% and ran the pump for 8 hours. The next day my chlorine level was a 2. The water temp has ranged from about 62 to 68 degrees. I then ran it at 100% for 8 hours and it still was a 2. My SWG is displaying no errors or faults and it is brand new out of the box. Salt level is 3000. Is it not producing extra chlorine due to the water temp or is something else wrong?

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Do you have a FAS-DPD chlorine test? What you need to do is confirm whether or not there is anything growing in your pool and to do so, you need to perform and overnight chlorine loss test (OCLT). You need a recommended test kit. You cannot maintain a pool properly without it and cannot get advice from us without it. See here: Pool School - Test Kits Compared

    Do you know what your salt level is at? Does your SWG give you a salt reading or a low or high salt light?

    Filling out your signature in your profile would help a lot as well. More details about your pool are needed.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    I have a Taylor K 2005 DPD Test Kit
    Taylor Technologies K-2005 DPD Complete Chlorine Kit

    My salt was measured by the pool store at 3000. Recommended range for mine is 3000-4000, with the ideal being 3500. The unit itself has a display and shows the check mark in the correct line to indicate it is adequate. It would tell me if it was low or high. It claims to produce 1.38 pound of chlorine per day (which I assume is if it is running 24 hours a day at 100%). My pool is 22,500 gallons.

    And I just order 3 Liters of Phosfree...

    And I filled out my signature.

    Thanks
    18'x36' Inground Kidney Shaped Pool, 22,500 Gallons, Buddy Seat, Vinyl Liner, Hayward Super Pump 1.5 HP, Hayward Pro Grid DE Filter, American SPS Resilience A5 Salt Water Generator, (5) Sunheater 2'x20' Solar Panel Heater Setup with Goldline Automatic Valve and Thermostat Box, Raypak 360,000 BTU Digital Cupro Nickel Natural Gas Heater, Polaris 380 Cleaner with Booster Pump, Pentair Intellibrite 5g LED Light

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    You don't have a test that can directly measure CC in the K-2005 kit. The K-2006 has it or you can order the individual test for FAS-DPD. I believe it's the K-1515-A from Taylor or the same test from tftestkits for cheaper is here: FAS-DPD Test

    You need to be able to test for CC to indicate whether or not something is growing in your pool.

    I would attempt to perform this test with your current kit, but you need a FAS-DPD test to properly manage your pool and diagnose problems: Pool School - Perform the Overnight FC Loss Test (OCLT)

    I'm not sure why you decided to buy Pho$free. Your phosphates are already low and honestly, phosphates mean NOTHING in a pool that's properly sanitized. Spend some time in Pool School to familiarize yourself with our methods here such as ABCs of Pool Water Chemistry and the links in my signature.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Also, for future reference, a vinyl pool doesn't need calcium added. Unless you have a heater perchance? Then you could need it to protect the heater, but it does nothing to the vinyl.

    Again, as mentioned a couple times already- You need that FAS-DPD tester and your K-2005 does not contain it. It is the chlorine test that will read up to 50ppm which is important when you're trying to SLAM a pool clean. Your current test only goes to 10ppm.
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Agree all around with the stop-pool-store-testing. But if you measured the fc spike after a gallon of 12%, but can't see anything with your swg running, it's not directly a test error. Bad salt level test, bad flow through the salt chamber, something like that. Do a search here, I think some people have.tried to capture water directly in front of the return to measure their swg's output manually, before it gets diluted in the pool.
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Welcome Tom. I would take that phosfree hocus pocus back to the store and return it.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    I appreciate all the good advice. Im going to purchase that add on for my existing test kit and see what I come up with.

    As for the CH, I added it because I have a natural gas heater. (I also have a solar heater setup too)


    The SWG I have will show error codes for low salt, high salt, wire connection issues, flow sensor issues, low water temp, etc. It seems pretty advanced.


    Ill post an update in a few days

    Thanks!
    18'x36' Inground Kidney Shaped Pool, 22,500 Gallons, Buddy Seat, Vinyl Liner, Hayward Super Pump 1.5 HP, Hayward Pro Grid DE Filter, American SPS Resilience A5 Salt Water Generator, (5) Sunheater 2'x20' Solar Panel Heater Setup with Goldline Automatic Valve and Thermostat Box, Raypak 360,000 BTU Digital Cupro Nickel Natural Gas Heater, Polaris 380 Cleaner with Booster Pump, Pentair Intellibrite 5g LED Light

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    "The SWG I have will show error codes for low salt, high salt, wire connection issues, flow sensor issues, low water temp, etc. It seems pretty advanced."

    SWGs can throw error codes out that aren't accurate too. Some folks find that out when they see a "high salt" or "low salt" error yet they independently test the salt level and it isn't what the unit thinks.

    Bottom line, and oft repeated, "If the SWG is happy (and producing chlorine) leave it alone"
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
    Our pool build--> Our Pool Solved Our Sloping Yard Skippy's Cheap Pool Cooler -->Skippy's New Fountain

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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    So while await delivery of the add on FAS-DPD test kit, I heated up the pool from about 66 degrees to 80 degrees. (We had a temperature spike in NJ and it was suddenly 87 degrees out, family wanted to go swimming). As I tested the chlorine level with my standard kit, it appears that the SWG is now cranking out chlorine as it should. I'm wondering if the low 60 degree water was part of my problem too.

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    Mod Squad JVTrain's Avatar
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    Re: Pool water looks perfect, no chlorine level, 30ppm nitrates, do I drain?

    Most SWGs will start to operate somewhere between 50 and 60 degrees. In the 62-68 range you reported in the first post, it most certainly should have been running as long as salt levels were OK. Every SWG I've ever read about runs at those temps easily so that's why I was more inclined to think that you had something in your pool consuming FC faster than your SWG was putting it out than the SWG not working.

    Glad it seems to be working now. I would still encourage you to test for FC and CC once you get your add on test and report full results along with them when you do so.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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