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Thread: Pool is eating Chlorine INSTANTLY!!!!!

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    Pool is eating Chlorine INSTANTLY!!!!!

    Today I picked up a pool that was firing another pool company in the area. The pool was opened back in May, but hadn't been touched since until a few days ago.

    When I arrived this morning, the pool didn't look as bad as I thought it would. I could see the bottom in the shallow end, and the pool had a cloudy blue color. I tested the water with a test strip (I know, not the best) and saw no FC, no TC, very low pH, low TA, low CH, low CYA. I started hitting the pool with chemicals. I put in 16lb of trichlor shock. I tested between shocks, and I kept finding that by the time the water came out the return jets, the FC was zero. I added about 25lb of Cal-Hypo, and again, the FC didn't budge. I did start to see Total Chlorine readings after both additions, but no FC. I was able to get a very low reading a few times right at the return jet, but a few feet beyond it was zero again. I started adding 12% liquid chlorine. I put in over 30 gallons, and I still can't get an FC reading above zero. These additions of chlorine weren't all at once, I made 3 visits to this pool.

    When I added the granular chlorines through the skimmers, they bubbled vigorously, and I could see the yellow chlorine gas bubbling out. When I added the liquid chlorine, I could see a fine fizzing as the chlorine was dispursed by the return jet.

    I know it wasn't the test strips going bad, because they worked fine on every other pool I worked on today, and I also tried a brand new pack. I even poured liquid chlorine on one to make sure they were reading. The only other chemicals I added to the pool today were pH increaser and Polyquat.

    I'm assuming that the pool was cloudy blue instead of blackish green because of the polyquat killing the algae.

    So my initial thoughts were ammonia. I figured I should be able to add enough chlorine, and eventually the ammonia is used up, and the FC will come up. After using more chlorine than I use in a month on all my other pools combined on just this pool in a single afternoon, I'm questioning that idea.

    Is there anything else that could be doing this? This is the first time I've seen anything this bad. I've seen pools with ammonia, but usually after a few pounds of trichlor, they are back on track.
    TreeFiter

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    Saugerties, NY

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    JasonLion's Avatar
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    You should do an ammonia test. You can pick them up easily at aquarium stores. That will tell you how much further you need to go, and give you an idea if draining is a more appropriate response.

    We have seen pools that needed hundreds of ppm of chlorine. That kind of extreme is quite rare, but then the bubbling behavior you described is also quite rare and likely caused by very high ammonia levels.
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Quote Originally Posted by JasonLion View Post
    You should do an ammonia test. You can pick them up easily at aquarium stores. That will tell you how much further you need to go, and give you an idea if draining is a more appropriate response.

    We have seen pools that needed hundreds of ppm of chlorine. That kind of extreme is quite rare, but then the bubbling behavior you described is also quite rare and likely caused by very high ammonia levels.
    Thanks Jason, I was about to head to PetSmart to pick up an ammonia test kit. It sounds like I'm probably on the right track.
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    I picked up an aquarium test kit, but the ammonia test only goes up to 8ppm. What do I do if the ammonia concentration is more than 8ppm, and how much chlorine should I need to remove ammonia? Is it 1ppm FC to remove 1ppm Ammonia? I've already added close to 250 ppm FC, so I have a feeling I'm dealing with more than 8ppm Ammonia.
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Maybe dilute the pool water 1:3 or 1:5 with tap water and multiple the test result accordingly (x4 or x6) ?

    IIRC it takes something like 10 ppm FC per 1 ppm of ammonia. Guessing the pool started with very high CYA level => very high ammonia level => Richard320's favorite Clorox tanker truck to remove it.
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    It's roughly 10x the ammonia level as cumulative FC to get rid of it. If you want to measure higher than 8 ppm, you can dilute the sample with tap water (note that if it is chloraminated, then this will report as ammonia but even 4 ppm CC as monochloramine will only show up as 0.8 ppm ammonia and most chloraminated tap water is closer to 1 ppm CC).

    So if you register 8 ppm ammonia, then it's probably better to do partial drain/refill to reduce the ammonia level rather than add 80 ppm FC or more of chlorine that can get expensive.
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Quote Originally Posted by TreeFiter View Post
    When I added the granular chlorines through the skimmers, they bubbled vigorously, and I could see the yellow chlorine gas bubbling out.
    That can't be good for the pool equipment!
    20,000 gal in-ground plaster pool with sand filter. Replastered recently. Mostly adding bleach and acid. CYA was high when I took over.

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    I picked up an aquarium test kit, and it confirmed a significant presence of ammonia. Tested above 8ppm, so I diluted a sample by half and tested again, still over 8ppm. I hit it hard again with liquid chlorine, and I noticed that the fizzing had slowed down, and I could get a FC reading on a test strip for about a minute after adding each carboy. By the time I finished adding the last of the liquid chlorine, I found the FC was staying, although low. I added 4lbs of trichlor, and began to bring up the pH and Total Alkalinity. I think I can see the light at the end of the tunnel.

    I found out from the owner of the pool today that the pool was never opened last year, which would explain how it got so bad. He told me that the pool guy I replaced claimed that the problem was white mold.

    So at this point, the ammonia appears to have been neutralized, I added an additional 12ppm FC to the pool (trichlor), a quart of Polyquat, brought the TA up to about 90, and the pH up to about 6.8. I guess now all I can do is let it filter and keep the FC up. What are my chances this pool could clear up by the weekend?
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Once the ammonia is out of the way, I imagine the pool should behave "normally". The remaining cloudiness/algae doesn't sound too bad so getting it all killed by the weekend seems possible, but I guess at that point it's going to depend on how effective the filter is.

    Maybe take the pH a bit higher first since (a) you won't be able to test accurately when FC is way up there and (b) trichlor will pull the pH down a bit further ?

    BTW I *think* you are the new record holder for reported ammonia levels here
    Cedar hot tub, 680 US gallons - Snorkel wood-burning heater, canoe paddle, "offline" Intex 1000 GPH pump/filter with skimmer

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Wow! An amazing time line!!

    Seriously, fizzing water?!?! That's gotta be a one-of-kind story here on TFP.



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    Re: Pool is eating Chlorine INSTANTLY!!!!!

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    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    If you have all that ammonia, you should NOT be adding stabilized chlorine until the end. Why are you using test strips? How are you going to return a pool to the owner and be confident you cured the pool of all organic matter, including ammonia, by using strips?
    I'd bet you my bikini you'll never get TFP water from a pool store!

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    The pool is equipped with a Sta-Rite System 3 Cartridge filter. I'm thinking that should filter pretty efficiently. I'm going to try to get the pH up to where it needs to be today, and hopefully I see some results. I told the customer from the start that I couldn't promise the pool would be ready by the weekend, but I would do my best to get it there. It would be really nice to be able to make it happen for him.

    The fizzing water was a first for me. It took somewhere around 250 ppm FC to overcome the ammonia.

    Looking back, I wish I did take some pictures or videos. At the time I was too busy trying to figure out what the heck was going on.
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Quote Originally Posted by Casey View Post
    If you have all that ammonia, you should NOT be adding stabilized chlorine until the end. Why are you using test strips? How are you going to return a pool to the owner and be confident you cured the pool of all organic matter, including ammonia, by using strips?
    I'm using a combination of test strips and a TF-100. Test strips will get me most of the way there, and I will confirm everything with the TF-100. The customer is a weekender, so the plan is to keep me on long term for weekly maintenance going forward.

    Taking care of pools on a weekly basis is a bit different than the TFP method. It is cost prohibitive to be there every day testing FC, so I have to plan ahead and keep the FC on the high side, and rely on automatic chlorination. Unfortunately this means that unless they have a salt system, they are still using tablets, but here in the northeast, we drain and fill enough when closing and opening the pool that it takes a while for the CYA to build up. Its not ideal, but it works pretty well.
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    With that much conversion of ammonia just note that you will have higher nitrates (shouldn't be a problem), but may also have some leftover nitrogen trichloride (trichloramine) that may stink. It's very volatile so aeration of the water, especially with a breeze or wind, can help remove it. As low as 20 ppb is noticeable by smell so that will only be 0.02 ppm and not be large enough to show up as CC in a test kit. If you get to the point where the water doesn't smell bad, you should be in good shape at least as far as the ammonia is concerned.
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Still not completely out of the woods just yet, but in much better shape than I started. FC dropped from about 40ppm last night to zero by 11am today. I brought it back up to about 40 ppm, and I came back around 6pm, and it had fallen to around 32ppm. The good news is that the pool is already starting to clear up. Yesterday, I could see about halfway down the slope, and today, I was able to see dark shadows in the deep end where piles of dirt and debris where. I was able to vac out everything I could see. I'm thinking there is a realistic chance that this pool will be clear for the weekend.

    As for the chloramine smell, there is a slight odor, especially right after adding liquid chlorine. I'm thinking there is still a small amount of ammonia in there (it was down to 0.25ppm this morning) and it did test around 2ppm for Chloramines. At least at this point, the chlorine is staying long enough to start working.

    I also got the pH up to within reason. I added 30lbs of pH increaser and it looked like I was sitting right around 7.2 when I left.

    Once its clear, the next big project will be removing the iron stains, but first I want to let these people enjoy their pool for a few days before I start messing with things again.
    TreeFiter

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    Saugerties, NY

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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    The slower chlorine loss you are now seeing is probably partially degraded cyanuric acid. Basically the bacteria didn't finish it off. Such by-products are more slowly oxidized by chlorine. You should be done in a few days.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: Pool is eating Chlorine INSTANTLY!!!!!

    Yesterday afternoon, the pool still had FC of about 22ppm after almost 24 hours. The rest of the chemistry is looking pretty good. The pool was clear enough to see the bottom drain, and any algae I missed with the first vacuuming.

    I bumped the FC back up above 35ppm, and I expect the pool to be clear by this afternoon. The customer seems pleased.

    The next big thing will be the Iron stains. The entire shallow end of the pool is stained really bad, along with the steps. I'm looking for ways to actually get the Iron out of the pool rather than just sequester it. I've read about Culator a few times now, but I haven't heard of anyone actually having any real success with it. I've also read about a few techniques using pillow stuffing, but I haven't seen a full description of how this is done. Does anyone know more about either of these?
    TreeFiter

    Pool Technician
    Saugerties, NY

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