Chemicals not testing right

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Chemicals not testing right

Postby zRiddle » Sat 03 Dec, 2011 17:17

So I work at a hotel on weekends. anyways, I went to test my ph, al and ch. When I went to test the AL the test sample turn to a clear color. which the sample has never done before. Today when i got to work the spa was closed down. a guest had said the water turned her bathing suit white which is was once pink. so the spa is still closed sence i have no way of testing the chemicals. the pool reads normal. but im unalble to test the CH and Al the ph is testable but always read high when i now its not. so why would the AL and Ph not test correclty. I have not seen the spa water turn any different colors. Its fairly clear. What could I do to get the spa open tonight. thanks.

chem geek
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Chemicals not testing right

Postby chem geek » Sat 03 Dec, 2011 17:34

Your chlorine level is extraordinarily high -- so high that it is bleaching out the Total Alkalinity (TA) indicator dye, is giving a falsely high reading for pH (blue/purple), and is bleaching people's swimsuits. If you are using a DPD chlorine test, the kind that is different intensities of pink/red indicating the chlorine level, then at high chlorine levels above 10 ppm it will bleach out to be clear having you think there is no chlorine when it is really very high.

For a commercial/public pool or spa you really should be using a better test kit such as the Taylor K-2006 which uses a FAS-DPD chlorine test that will not bleach out at high chlorine levels (if you see a flash of pink, you add more DPD powder). Also, if the chlorine level is high in this kit, the TA test will go from blue-to-yellow instead of green-to-red. You can read more about test interferences in this link.

Until you get a better test kit, you can dilute the spa water with tap water or better yet distilled water to test the chlorine level. You may need to dilute 5:1 or even 10:1 depending on how high the chlorine level actually is. Though tap water will have some chlorine in it, it will be lower than your spa water so won't interfere with that too much -- at least for a rough estimate.

Chemicals not testing right

Postby zriddle » Sat 03 Dec, 2011 17:49

alright that makes sence. Im adding some dechlour. Ill let you know how it goes thanks again. :D :)

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