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Thread: UV/Chlorine Pool

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    UV/Chlorine Pool

    I am getting ready to start a new in-ground pool project and was planning to use a UV system to sanitize the pool water in combination with chlorine at a low level to clean the pool surfaces. My sister and brother-in-law are highly recommending this type of system and I like the look, feel and smell of their pool. After looking through this forum however this type of system is not discussed or even mentioned. Do these systems have a bad track record or are they just relatively new compared to the other pool sanitization systems that are typically discussed here? I would love to hear from anyone that has any experience with this type of system.

  2. Back To Top    #2
    linen's Avatar
    Join Date
    Jul 2010
    Twin Cities, MN

    Re: UV/Chlorine Pool

    Welcome to tfp, jailbreak

    UV systems are generally not needed on outdoor residential pools. You will still need a sanitizer such as chlorine. Take a look at this post for some detail:
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Isaac-1's Avatar
    Join Date
    May 2010
    SW Louisiana

    Re: UV/Chlorine Pool

    Chances are what you notice about their pool is it is well balanced, this may be on purpose or may be an accident, it is certianly possible to do this without a UV sanitation system, it is also possible to have an out of balance pool with UV sanitation. The thing about UV systems is they can only treat the water that passes through them, not the stuff that may be growing in your pool and clinging to the sides, under the ladders, etc. to kill those things and to keep them from growing in the first place you need chlorine in the water. The simple reality of the sitution is most outdoor pools get more than enough UV from sunlight to reduce the CC products if they are properly balanced, having a UV system may extend the comfort zone of this balanced range a little, and if you have money to burn there is no harm in it.


    p.s. Keep in mind "that chlorine smell" that most people complain about around pools is really combine chlorine products, which is often a sign of a pool with too little chlorine in it, not too much, a simple example of this, is go open a bottle of unscented chlorine bleach, carefully smell it, you will not smell much chlorine smell, in fact the bit you do smell is likely causes by the chlorine reacting in your nasal passages forming those dreaded combined chlorine products (this is the same as when you get bleach on your hands, etc.).
    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
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  4. Back To Top    #4

    Re: UV/Chlorine Pool

    Thanks for the feedback. As I mentioned in my original post, I am aware of the need to maintain a residual chlorine level sufficient to kill algea on and sanitize pool surfaces. My sister indicated they try to keep their chlorine level between .5 and 1 PPM. This lower chlorine level and the UV system seems to be working well for them but I'd like to tap into a broader experience with this type of system via the forum. The idea of being able to keep the chlorine level low and still have a safe and well balanced pool appeals to me. Does anyone out there have any extended experience with this type of setup? I'd like to hear about other people's experiences if they don't mind sharing them.

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    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: UV/Chlorine Pool

    How do they keep chlorine between .5 and 1ppm? Frankly, I don't think that's doable.

    A typical pool will use 2-4ppm chlorine daily so it would be virtually impossible manually and even with a stenner pump or SWG that is a tiny, tiny range that sounds nice on paper but, in reality, isn't practical.

    Municipal tap water is commonly around 2ppm chlorine and millions drink it. When you put Clorox in your washer and put your hands and clothes in it, it is about 300ppm.

    3-5ppm in a chlorine pool needs to be kept in perspective.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6

    Re: UV/Chlorine Pool

    I don't know what test kit or method they use to check the chlorine concentration but I know they add their chlorine in the evening so they can get the most from its effects during the night. I think they do their testing for chlorine concentration, ph, etc. in the morning. As long as the chlorine level is in the range they want when they check it in the morning, I don't think they worry about what happens to the chlorine level during the day because the water is being sanitized by the UV system. If the chlorine level isn't what they want in the morning I think they wait until that evening to adjust the amount of chlorine they add. I'll pay closer attention to their methods and chemicals the next time I'm there.

  7. Back To Top    #7
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: UV/Chlorine Pool

    Only the water passing through the cell is exposed to UV.

    UV has no advantages for a residential pool unless you routinely have large pool parties. Many UV systems also use up chlorine. Chlorine alone does everything that needs to be done, leaving nothing for the UV system to do. You have to have a residual sanitizer in the water, so you have to have chlorine. Perfect water is easy to obtain less expensively without UV if you follow our recommendations. The main comments about UV systems we hear around here are of the form: "I noticed the the bulb had burned out on my UV system long ago, but I never noticed any difference."
    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

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