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Thread: Cannot raise Free Chlorine/slight green water

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    Join Date
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    Cannot raise Free Chlorine/slight green water

    Hello,

    Years ago, this forum helped me greatly fix a problem with my pool water. We have had no problems until we opened our pool May 30. For the first time, when we opened our pool the water was green. Not horribly green, but green nonetheless. We brushed the walls, shocked the pool (powder packets), let the filter run a lot, and then had the water tested at our local pool store. They kept telling us to shock it, use algaecide, etc. We shocked it, added the calcium they told us to use, used the algaecide, and shocked it again. It still looks slightly green, although it is mostly clear.
    Today I went to the pool place again and they now told me that my nitrates are very high and that I need to drain the pool in 6 inch increments. The level of free chlorine is .4 and the nitrates are 10 ppm.

    I wanted some expert advice about whether draining the water a little at a time was the only way to deal with this problem.

    Thank you for any help you guys can send my way,

    Renee

    33,000 gal, inground, vinyl liner pool.

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    Mod Squad JVTrain's Avatar
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    Re: Cannot raise Free Chlorine/slight green water

    First of all, welcome to TFP! Glad you found us.

    First things first. Your best bet is to familiarize yourself with our methods and what we teach here. The best place to start is ABCs of Pool Water Chemistry. Our methods revolve around reliable home testing of your pool water using a recommended test kit. This is a comparison of comparable kits. Pool School - Test Kits Compared The best kit, hands-down for having everything you need and having enough reagents to last you an entire season is the TF-100 from tftestkits.net. Link is in my signature. Home testing is more accurate, more convenient and designed to tell you what your pool needs when used with our methods, rather than what the pool store is trying to sell you.

    Green pools and cloudy pools are almost always issues with sanitation. That is, chlorine levels dropped to levels that were not able to handle bather waste and prevent algae from starting, so now it must be handled with more chlorine until it is eliminated. Your test kit and our SLAM procedure (link also in my signature) allow you do definitively eliminate algae and also know when it has all been eliminated. The answer is bleach through this process. Not powdered forms of chlorine, as they all add something undesirable for the long term maintenance of your pool.

    It's a lot to take in at first, but start with the ABCs and ask questions!
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Jun 2016
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    Jackson, NJ
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    Re: Cannot raise Free Chlorine/slight green water

    Thank you for your reply. I'm going to order the kit in the morning. IN the meantime, I will continue reading the areas you mentioned. I am curious if you are saying that the pool store's recommendation to drain 6 inches at a time to get rid of some nitrates is not necessary?

    We will go back to using bleach to shock the pool, using the SLAM method as you suggested. Can I begin this before my test kit arrives? I'm also concerned that the bleach (we had been using Clorox intermittently for a few years, has bleached my liner. Is that typical, or is that perhaps just from being an older liner? We are going to need a new liner by the end of this season and it's quite expensive for our large pool and I don't want to bleach it (the new one will be a dark blue)

    Thank you so much, and I'm sure I'll have more questions,

    Renee

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    TFP Guide

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    Re: Cannot raise Free Chlorine/slight green water

    I would not drain at least not for nitrates. Best to not try to start SLAM before the kit arrives most likely a waste of chlorine to just blindly add without test results and it could skew recommendations when you are able to post test results.
    12,300 Gallon, IG PebbleFina, 3 ft sheer, 2 Jandy nicheless LED lights, Jandy Pro 1.5HP VS pump (A.O. Smith Motor), PB4-60 Booster pump, Polaris 280, Jandy cv340 cartridge filter, Zodiac Z4 control panel W/iAquaLink, Stenner pumps for chlorine & MA connected to WiOn WiFi switches, TF-100. You can support TFP with AmazonSmile just click the link!

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    Mod Squad JVTrain's Avatar
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    Re: Cannot raise Free Chlorine/slight green water

    Nitrates are fairly irrelevant in a pool and simply another number the pool store is throwing at you to get you to spend money and/or drain your pool. You may have to drain your pool, but not because of nitrates. If your CYA (stabilizer) level is too high, it may require unmanageable levels of FC to maintain a sanitized pool.

    When using bleach, it's perfectly safe for your liner provided you are adding it correctly. It should always be added in front of a return jet with your pump running. Add it slowly. Aim for a pencil with stream from the bottle. Letting the bottle float in the pool while you hold it makes it easier to hold and pour slowly. When you're done adding the desired amount, a good, quick way to make sure none has settled to the bottom is to brush the area immediately below the return where you added it. Don't add bleach to a skimmer. Don't spread around the outside of the pool, unless you'd rather brush the whole pool immediately to make sure it hasn't settled everywhere.

    The only thing I chlorinate with all summer is bleach. Liner doesn't look any worse than when I inherited it with the house.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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