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Thread: Ozone generator and chlorine levels

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    Ozone generator and chlorine levels

    Hi everyone. Here's my first post! I'm glad I found this community.

    I searched the forums and could not find a topic related to this issue.

    We just installed a brand new 450 gallon Artesian (Island Spas) spa. The place we bought it from provided a suite of Leisure Time chemicals including SPA 56 chlorine.

    It has a Del Ozone plasma gap ozone generator and I am having trouble finding out what chlorine level to run. The people at the spa dealer said that the ozone causes the chlorine level to read low, but I did some research and learned that the ozone destroys the chlorine, which my testing results prove to be true. With a clean city water fill (FCL of 1.04), I can add enough chlorine 56 to bring it up to more than 3 ppm and one day later it's at less than 0.5 without using the spa at all. The filter and ozone default to running 24/7. Water is crystal clear.

    So my question is what chlorine level should I be running? Should I follow the normal spa recommendation for a level of 3-5? If so, I would need to be adding chlorine every day, but I would rather err on the chlorine level being too high than too low. I had issues with cloudy water and foam at first and ending up changing the water twice in less than a month. I use a ColorQ test kit to get my results because I am colorblind and the test strips and 5-way test kits are impossible for me to read.

    City water test results

    FCL 1.04
    TCL 1.18
    PH 7.1
    ALK 150
    CH 227

    Just after filling and adding 0.45 oz by weight of the chlorine (maybe a bit too much), here are my test results:

    FCL 6.15
    TCL 9.12
    PH 7.2
    ALK 138
    CH 255

    After 24 hours without using the spa these were the results:

    FCL .20
    TCL .40
    PH 8.0
    ALK 147
    CH 223

    I am working to get rising PH and ALK levels down, which is also proving a challenge. On a daily basis I can add enough dry acid (about 2.5 oz by weight) to lower the PH to 7.0 (per the pool calculator), and it's back to 8.0 in a few hours. The alkalinity will drop by less than 10 points after each treatment. Is this normal? The amount of water testing I need to do (several times per day) is making me feel more and more like a chemist.

    Thank you!
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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    Mod Squad JVTrain's Avatar
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    Re: Ozone generator and chlorine levels

    You'd be best served following the guidelines of the How do I use Chlorine in my Spa (or pool)?) sticky. The Spa 56 product is dichlor. So, you would use that to add in total over the start up period of the tub, 30-40 ppm of FC. Not at the same time, of course. Right after fill, I'd add enough of the dichlor to bring the FC up to 10-12 ppm. Then dose up to 5-6 ppm each time you check the spa again until you've added a total of 30-40 FC by using the dichlor. Then switch to bleach only after that. It's all in the sticky.

    The TA will come down as you add acid to bring the pH down. It just takes time but with the massive amounts of aeration you get in a spa, it doesn't take long for the pH to rise at higher TA levels. Once you are in the 50-60 ppm TA range, don't add acid until the pH rises to 8.0 and only bring the pH down to 7.4 when adding acid in that TA range. You can consider borates as an OPTION at that point.
    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: Ozone generator and chlorine levels

    Joel, Thank you. The sticky is very good information. I did not realize that the dichlor added CYA. I tested the level and I'm at 17 ppm CYA now.

    According to what I'm reading, I will need to be using a lot more chlorine than the "1 capful a week" that the spa store recommended. No wonder I had cloudy water and foaming!!

    I will be patient and continue to add acid to get the TA lowered to the proper level. Too bad I didn't know about the relationship between CH and TA. When I filled the spa, I turned off my water softener to get the CH level up, but next time I drain and fill, I will try to mix softened and un-softened water to get the CH levels lower so I don't have such an issue to get the TA lower.
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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    Mod Squad tim5055's Avatar
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    Re: Ozone generator and chlorine levels

    Quote Originally Posted by wilzy5 View Post
    Joel, Thank you. The sticky is very good information. I did not realize that the dichlor added CYA. I tested the level and I'm at 17 ppm CYA now.

    According to what I'm reading, I will need to be using a lot more chlorine than the "1 capful a week" that the spa store recommended. No wonder I had cloudy water and foaming!!

    I will be patient and continue to add acid to get the TA lowered to the proper level. Too bad I didn't know about the relationship between CH and TA. When I filled the spa, I turned off my water softener to get the CH level up, but next time I drain and fill, I will try to mix softened and un-softened water to get the CH levels lower so I don't have such an issue to get the TA lower.
    How are your testing to get 17 CYA?


    ********On Edit

    I now see the ColorQ

    Please do not confuse the specificity of the readings the ColorQ provides with accuracy. Many people have tested them here and the accuracy does not hold up to the test of time. One person posted a few months ago he rested the exact same water sample three times in a row and got 3 different sets of test results.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Ozone generator and chlorine levels

    Tim - yes, I am very aware of the variability of the readings from the ColorQ. I was trained in the 6-sigma methods of understanding process and measurement variation. I have not performed a measurement system analysis for the ColorQ just yet, but I usually take a large sample of water, let it cool to room temperature, then conduct 3 groups of tests, taking three repeat readings of each group and then average all 9 readings together. I can only read the TCL on the repeats, but I found that the variability within the group repeat measurements is lower than the group to group variation.

    For a sanity check, I then compare the PH and alkalinity with the results I get from my 5-way kit, and then just for fun, see what the cheap-o test strips say. For now, they are all in agreement that my PH and Alkalinity are too high. As I stated earlier, for the past few weeks, I feel like a part time chemist.
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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    Re: Ozone generator and chlorine levels

    the cya test in the recommended test kits is just looking at the obscurity of a dot in cloudy water, so it might be worth it to get must that test if you can.
    10,500 gal IG, Topaz Pebble, auto-level
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    Re: Ozone generator and chlorine levels

    I just looked at the Del Ozone website and they are advising that the chlorine level needs to only be 0.5 ppm or Bromine levels at 1 ppm. They seem to be advocating that an ozone system can reduce the need for traditional sanitizers.

    Hot Tub or Spa Water Troubleshooting | Spa Water Maintenance
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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    JoyfulNoise's Avatar
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    Ozone generator and chlorine levels

    Quote Originally Posted by wilzy5 View Post
    I just looked at the Del Ozone website and they are advising that the chlorine level needs to only be 0.5 ppm or Bromine levels at 1 ppm. They seem to be advocating that an ozone system can reduce the need for traditional sanitizers.

    Hot Tub or Spa Water Troubleshooting | Spa Water Maintenance
    Yes, because they want to sell you a expensive toy.

    Please use the search box and look up terms like "alternative sanitizer" "ozone" "low chlorine". This subject has been extensively discussed here and chem geek has posted many responses on the subject. The claims these manufacturers make do not stand up to any intellectual scrutiny. Ozone increases chlorine demand and rarely, if ever, reduces chemical costs.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Ozone generator and chlorine levels

    Quote Originally Posted by JoyfulNoise View Post
    Yes, because they want to sell you a expensive toy.

    Please use the search box and look up terms like "alternative sanitizer" "ozone" "low chlorine". This subject has been extensively discussed here and chem geek has posted many responses on the subject. The claims these manufacturers make do not stand up to any intellectual scrutiny. Ozone increases chlorine demand and rarely, if ever, reduces chemical costs.


    Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
    So much good info on this site. I am treating my spa as if it does not have an ozone generator. I am not finding anything that says that chlorine at normal levels plus ozone is a bad thing. I see lots of bad things that can happen from having too little chlorine.
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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    JoyfulNoise's Avatar
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    Ozone generator and chlorine levels

    Quote Originally Posted by wilzy5 View Post
    So much good info on this site. I am treating my spa as if it does not have an ozone generator. I am not finding anything that says that chlorine at normal levels plus ozone is a bad thing. I see lots of bad things that can happen from having too little chlorine.
    In a spa, ozone can supplement the oxidation of organics and bather waste allowing one to use less chlorine after a soak. BUT ozone also reacts with chlorine converting active chlorine (hypochlorous acid) into chloride. So, unless you have the ability to run the ozone generator separately from the circulation system, then a constant ozone source will create an excess chlorine demand when the tub is just circulating water.

    As well, ozone is not an effective sanitizer so it does little to kill pathogens.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Ozone generator and chlorine levels

    Quote Originally Posted by wilzy5 View Post
    I just looked at the Del Ozone website and they are advising that the chlorine level needs to only be 0.5 ppm or Bromine levels at 1 ppm. They seem to be advocating that an ozone system can reduce the need for traditional sanitizers.

    Hot Tub or Spa Water Troubleshooting | Spa Water Maintenance
    0.5ppm would be an adequate chlorine level in a spa with no stabilizer. However, that chlorine level will only last about 20 minutes. With stabilizer and chlorine (in the right ratios), you can still have the same level of ACTIVE chlorine as 0.5 with no stabilizer, but the additional chorine that is bound to the stabilizer slowly releases into the water all day as the active chlorine is used up.

    Don't look at the FC level as the current active chlorine level. You might think that a FC of 5, or 10, is 5 times or ten times harsher than a pool with "only" 0.5 or 1ppm. That is only true in water with no stabilizer. The point being, that you still need the correct residual (sitting in the water at all times) amount of active chlorine in your pool or spa to properly sanitize and prevent algae growth. If you dip below that correct amount (because hey the ozone will take care of it) you will have water in your system or spa that is not properly sanitized.

    Even running the ozone machine for 24/7 will not provide that level of protection, and that's why they can't advertise it as a sanitation system. Only as a supplement to proper chlorine or bromine sanitation.
    10,500 gal IG, Topaz Pebble, auto-level
    Hayward DE filter, 2HP Ecostar VSP, ProLogic PS-4, GVA actuators
    Cal Pools Wave Force Plus (wall return jets plus 2 floor pop-ups), Venturi Skimmer
    Water sheer, 2 wok pots, bubbler stem on the baja step
    ColorLogic Mutlicolor LED lamp. Taylor 2006+speed stir

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    Re: Ozone generator and chlorine levels

    Quote Originally Posted by BuckeyeChris View Post
    0.5ppm would be an adequate chlorine level in a spa with no stabilizer. However, that chlorine level will only last about 20 minutes. With stabilizer and chlorine (in the right ratios), you can still have the same level of ACTIVE chlorine as 0.5 with no stabilizer, but the additional chorine that is bound to the stabilizer slowly releases into the water all day as the active chlorine is used up.

    Don't look at the FC level as the current active chlorine level. You might think that a FC of 5, or 10, is 5 times or ten times harsher than a pool with "only" 0.5 or 1ppm. That is only true in water with no stabilizer. The point being, that you still need the correct residual (sitting in the water at all times) amount of active chlorine in your pool or spa to properly sanitize and prevent algae growth. If you dip below that correct amount (because hey the ozone will take care of it) you will have water in your system or spa that is not properly sanitized.

    Even running the ozone machine for 24/7 will not provide that level of protection, and that's why they can't advertise it as a sanitation system. Only as a supplement to proper chlorine or bromine sanitation.
    Thanks for the info Chris. I am now following the sticky instructions for the level of FC/CYA and measuring FC usage after each use to establish the FC demand. I was just surprised at how different the advice was from the company who supplied the spa, compared to what I have learned and observed/measured. The pool/spa people told me to "add one capful of dichlor per week" and that "the ozone causes the reading of FC to be lower than it actually is". This resulted in me having to drain and refill the water twice in the first two weeks. Then I found this forum and everything changed! Now I have crystal-clear water.
    14,000 Gallon IG vinyl pool with SWG, Island Spa 450 Gallons chlorine

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