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Thread: green water with oily film on top from adding baking soda

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    green water with oily film on top from adding baking soda

    My pool water was crystal clear but the water burned your eye when swimming. I read my total alklinity was the problem. When tested the ppm read 0. So I added baking soda (arm & hammer) are instructed. I turned the pool filter turn off and the water was still. I added 13.5 lbs for 30,000 gallons of water, the water instantly turn green which I read may happen. After 2 hours I turn on the filter and ran it all night. My water is still green with an oily film on top. I backwashed the pool and recharged it with DE. I retested the total alkalinity and it is still at 0. What happened? Do I have to add shock to turn the water blue again? Can you even swim in the water now? Its 90 degree out, did the heat have anything to do with the water turning green. I do not have a pool heater and the water temperature is 80 degree. The filter is running fine and my chlorine levels are all in the OK range. The pH is low at 6.2 but I read you have to fit the total alkalinity first then the pH. What did I do wrong?

    Any wisdom would be appeciated,

    Dolores

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    JasonLion's Avatar
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    Re: green water with oily film on top from adding baking sod

    Welcome to TFP!

    Ignore the green and the oily film and get your TA and PH levels up to something more reasonable right away. Low PH can damage the pool. I recommend using borax to raise PH, which will also raise the TA. But you can use baking soda or soda ash if you have them already.

    The oily film is probably organic oils and will go away once the PH has been at a reasonable level for a while.

    Assuming the water is a clear transparent green, the color is probably from metals in the water. It shouldn't cause any problems right away, so deal with the PH and TA first. If it is a cloudy hazy green then it is probably algae, but PH/TA still need to be dealt with first regardless.
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    Re: green water with oily film on top from adding baking sod

    Thanks Jason. The water is a clear transparent green. No algae. I only adding the baking soda because the water was burning everyones eyes. Should I add the Soda Ash first to get the pool water clear again and then continue with the baking soda treatment? If I continue adding the baking soda which calls for about 20 pounds and I only used the first 13.5 will the water get greener? Which do you I deal with first the low pH or the low total alkalinity. If I add the Soda Ash now am I looking for more trouble? By the way I tested the water that came out of the hose, which actually filled up the pool and the pH and alkalinity was in the ok level. What is causing the pool water to burn your eyes when you swim?

    Dolores

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    JasonLion's Avatar
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    Re: green water with oily film on top from adding baking sod

    The water is burning your eyes because the PH is so low. PH below 7.2 will sting or burn your eyes.

    Use soda ash if you have it to bring the pH up to at least 7.0. Then measure the TA again and see if it needs to be adjusted further.

    Something you added was extremely acidic. The most likely possibilities are PH Down, muriatic acid, dichlor or trichlor.
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    Re: green water with oily film on top from adding baking sod

    I haven't added anything to the pool except chlorine. I didn't even need shock this year. The pool water was clear when we opened and filled the pool. Can I add the soda ash now after adding the baking soda? Will the water get clearer faster. The kids will not swim it the pool now because its green. Should a get a super pool shock from Walmart first and add it just to get the water clear first and then add then add the soda ash tonight?

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    Butterfly's Avatar
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    Re: green water with oily film on top from adding baking sod

    No swimming. You should adjust the pH and TA before you worry about anything else.

    You can dose/test every 30 mins. with pump running until the pH and TA are right.

    Once the pH and TA are in line, you can then test/adjust chlorine, etc.
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    Re: green water with oily film on top from adding baking sod

    butterfy
    So what your saying is I should add the full 20 pounds of baking soda in the pool now and it will bring the total alkainity up and the pool will turn clear again.

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    Re: green water with oily film on top from adding baking sod

    What they are saying is to get the TA and pH correct. Only after these are in ideal ranges do you need to worry about the green in the pool. Fixing the TA and pH may get rid of the green but that is completely secondary to getting the TA and pH stabilized.
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    Re: green water with oily film on top from adding baking sod

    ping
    How do I do that? Add more baking soda? That's what turned the water greener in the first place. Can you add Soda Ash and Baking Soda at the same time, the both of them are basic ingredients. Why did the pool turn green in the first place after adding the baking soda. My pool was crystal clear before added the baking soda. Now its green and unswimable per butterfly. All I wanted to done was stop the eye burning. Now it seems I have a major problem on my hands. I'm adding all this natural stuff and we can't even swim in the pool. How long will the green color last and why did it happen in the first place.
    Totally frustrated. I just wanted to save a little money this year and use the baking soda instead of the alkalinity up from the pool supplier.
    Any help would be appreciated in explaining why the pool turned green from the baking soda?
    Thanks

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    Re: green water with oily film on top from adding baking sod

    I suspect that you were using Trichlor pucks/tabs as your source of chlorine, right? And you probably weren't testing your pH and TA regularly nor adding anything to compensate for the pH which would drop over time, right? Trichlor is quite acidic and requires regular addition of soda ash (pH Up; sodium carbonate; washing soda). If you measured a TA of 0, then that only happens at a pH of 4.5 (or lower) which is very low so you may have corroded copper metal from the heat exchanger in your heater (if you have one) and would also explain the burning of the eyes.

    When you added the baking soda, the pH and TA rose and the higher pH may have precipitated copper that was now in the water. You should get yourself a proper test kit, either the TFTestkits TF-100 or the Taylor K-2006. Otherwise, you can't really know for sure what is going on in your pool. Even with whatever test kit you have right now, what is the pH reading?

    As for the oily film on top of the pool after adding the baking soda, that one's a mystery.
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    Re: green water with oily film on top from adding baking sod

    Your were right the green water color was caused by the baking soda reacting with copper particles in the water that I was not aware we had. I spoke to a chemist friend and he mentioned metals would be the only reason the water would have turned a green color. He also said if the metal results where that high to turn the water green it would also effect the pH and TA results. I went to the local pool supplier and had the metal tested because most of the kits available did not test for metal. My Copper Result was a 3 and Iron was a 2, both should be at 0 ppm. We do have a heat pump that it is about 8 years old but it is still working. The pool supplier suggested we lower the pool level below the skimmer and refill the pool with fresh water and continue this until the water is clear again then have it retested for metals. I did have the pH and TA at the correct levels in the beginning of the season. The water has been crystal clear so I wasn't testing the pH and TA regularly, everything was fine until last weekend when our eyes were burning terribly. I tested the water and it show the TA was 0 and pH was 6.2. I have used baking soda before to bring up the TA and pH and never had a problem with the water turning green before. The pool supplier thinks its the copper in the water that is causing the eye burning and with that much copper the readings on the test strips for pH and TA will not show true. We do have the water running throught the heat pump even when the pump is not being used. The copper must be deteriorating without effecting the workings of the pump. I started lowering the water level and refilling the pool as they suggested. I will let you know the out come. Thank you for help.

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    Swampwoman's Avatar
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    Re: green water with oily film on top from adding baking sod

    This is more of a side note, but with iron at 2 ppm, you may want to test your fill water to be sure there's no iron in it -- if there is, you might wish to filter the fill water with a hose attachment or homemade filter to avoid adding more iron to the situation.

    I didn't see any details about your pool setup in your signature, or about what you're using to disinfect your pool, or whether you're using the bbb system -- or just parts.

    However, it sounds like you're using test strips. In the future, if you use an accurate drop kit like the TFT100 or the taylor 2006 (not 2005) you would know your exact TA weekly and be able to see there was a problem forming because you would notice your TA dropping in advance, before low TA and ph had a chance to harm any of your equipment and corrode the metal.

    So if you're looking to avoid a repeat situation, you may wish to consider a drop test kit, checking ph everyday and TA weekly. On one hand, crystal clear water is a sign that the water is not growing algae -- but it does not mean everything is "ok". That's why maintaining a log to chart
    your readings -- with the precision of the drop test -- is actually more the foundation of the bbb
    approach than using bleach and baking soda to save money is. Since everything reacts with everything, it's the knowledge that puts you in the driver's seat, not the product

    I don't want to jump ahead and I don't have experience with copper, but once you've got your TA up and your ph stable within parameters, if you need some tips about managing the iron I'd be happy to assist.

    If you want to test your fill water (are you on a well?) you can find copper tests at aquarium stores -- people with saltwater fish use them all the time.

    Best wishes for getting things under control, and keeping them there.
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    Re: green water with oily film on top from adding baking sod

    As for the chronology of how this happened, re this comment
    the pool supplier thinks its the copper in the water that is causing the eye burning
    The low TA and ph is normally what would cause the eyes to burn THEN possibly corrode the copper because it's so acidic. So my best guess is that unless you've been dosing with algicides that contain copper, the copper reading is actually a result of the acidic condition, not vice versa.
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