Checking PH after adding chlorine

[Fishy1234]

How long should I wait to check PH after adding chlorine? It's my understanding that chlorine can affect PH levels temporarily.

Also I am finding it hard to believe what a pool store person told me about CYA level increasing due to windy conditions. I went there to have it checked with there digital computer system. My last time at the store was over 6 months ago when the reading they gave me was 70 CYA, and now they are showing 108. I shook my head and left because she also told me to my PH was 7.9 and I checked it early at 7.2. Then she advised using soda ash to raise alkalinity up from 70ppm.

 

[Texas Splash]

How long should I wait to check PH after adding chlorine?

Give it about 20-30 minutes with good water circulation and you should get a pretty good reading.

As for the pool store test ......

 

[Richard320]

Give the chlorine fifteen or twenty minutes with the pump on to mix well before checking pH.

To a certain degree, the pool story lady is correct about CYA and wind. Wind causes more evaporation than just plain heat. Water evaporates, CYA does not. So until you replenish the water you lost, your CYA will be higher than it was. However, I doubt you would ignore the water loss long enough that it would register. A couple inches is only a couple percent, and that probably wouldn't show up in the view tube. And once you top it off again, the CYA will be back where it was.

Now: CYA raising from 70 to 18 is quite possible, if the Rainbow 320 trichlor feeder you show in your signature is still being used. I suspect it is, if you got 7.2 pH and she's trying to get you to raise TA. Trichlor doesn't just add chlorine and CYA, it's also very acidic and will drive pH and TA down.

 

[Fishy1234]

Thank you. I went to another pool store that uses Taylor products for testing and he gave me the same result as 6 months ago 90ppm CYA. Only issue I have with that store is they always say alkalinity is 120 or higher when my readings are low 70-80.

The main reason for asking about chlorine and PH is the PH was 7.2 at 12noon. At 6pm it was 7.8.

 

[Donldson]

Thank you. I went to another pool store....

Wait, why? Your signature states you have a k-2006, is this incorrect? Why do you need to go to any pool store for testing?

 

[Richard320]

Thank you. I went to another pool store that uses Taylor products for testing and he gave me the same result as 6 months ago 90ppm CYA. Only issue I have with that store is they always say alkalinity is 120 or higher when my readings are low 70-80.

The main reason for asking about chlorine and PH is the PH was 7.2 at 12noon. At 6pm it was 7.8.

Did you add any water during that interval? I don't even bother checking pH when I add refill water. I have learned through experience that 2" of water means another quart of acid in my pool. A whole bunch of aeration could do it, too. Aeration includes swimmers, especially the ones that do cannonballs and use kickboards and have splash fights.

 

[Fishy1234]

I have not used the Rainbow 320 since measuring CYA at 90ppm about 6 months ago. My pool has autofill for the water. I have kept the chlorine level above 7ppm for more than 3 months now, and water is crystal clear. I was hoping to see if the CYA level possibly dropped so I can lower chlorine usage.

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Wait, why? Your signature states you have a k-2006, is this incorrect? Why do you need to go to any pool store for testing?

With the Taylor test it is not easy to see where exactly the result is for the CYA test. I thought the digital tester pool store uses would be more accurate.

 

[Fishy1234]

Did you add any water during that interval? I don't even bother checking pH when I add refill water. I have learned through experience that 2" of water means another quart of acid in my pool. A whole bunch of aeration could do it, too. Aeration includes swimmers, especially the ones that do cannonballs and use kickboards and have splash fights.

I can hear the autofill working almost constantly in this high desert heat. How much water is being replaced, I have no idea, just know its working perfectly. Nobody uses my pool. Its 2 years old now, and wife has yet to put even a toe in the water. I tore my rotator cuff, and along with arthritis, tendonititus, and bursititus in right shoulder, its painful to swim. Although I have cooled off a few times after being in the sun.

 

[Fishy1234]

I am using a third to half gallon of 14% murriatic pool acid daily to keep the ph within range. With 1 spa spill over, and ozonator does it sound normal for Ph to rise so fast? pumps are running 4 hours at 3am, and 4 hours at noon.