High chlorine and PH reading

[Egreenwood]

I have been maintaining a higher free chlorine level around 10 due to my cyanuric acid creeping up this summer. Primary sanitizer this year has been trichlor due to reduced availability of bulk liquid chlorine in my area. The current issue is my water is slightly cloudy. This started when I corrected my low alkalinity and hardness about 2 weeks ago.
Current numbers with my taylor test kit:
PH: 7.2, Free Chlorine 11, combined chlorine - nil, Alkalinity 100, Hardness 220, Cyanuric acid 80-100.
I had been concerned my PH reagent was getting old. Stopped at pool store. They confirmed my readings except PH, they read PH 7.8 on a test strip. Bought a brand new taylor PH reagent, however my numbers continue to be the same with old and with new PH reagent. Tried 2 drops of thiosulfate, thinking maybe the chorine is affecting the PH reading, however I did not see any change. To my eyes, this looks like the cloudiness of a high saturation index, however the number do not support this. Any thoughts? Thanks

 

[reggiehammond]

pH is not accurate above 10ppm FC.

Trichlor is just adding more CYA and you’re already probably over the cliff of needing to drain a good bit of water to start over.

Cloudiness of the water is indication of algae, but your CYA levels make you a poor candidate for the SLAM process.

 

[Egreenwood]

In my area whenever I have had any algae in the past, I have had a green haziness. However this haziness is white. It is present some days and much less on other days. No algae is present on any surfaces. Is using the thiosulfate reagent from the alkalinity test a reasonable way to neutralize the chlorine to obtain a more accurate PH test. I typically move away from the trichor earlier in the year, however as I mentioned, there was a shortage. Fortunately the shortage has improved. However before I assume this is algae, I want to ensure that the haziness is not the result of a high PH and therefore a high saturation index. Are there any known ways to measure PH accurately in the setting of FC > 10 ?

 

[mknauss]

Is using the thiosulfate reagent from the alkalinity test a reasonable way to neutralize the chlorine to obtain a more accurate PH test.

No, the thiosulfate effects the pH.
Use Distilled water to cut the pool water FC

I see you have a painted pool surface. It is likely that is breaking down and causing the particulates that you are seeing.

 

[duraleigh]

If your FC is somewhere close to 11 ppm, Your pH reading is reasonably accurate. pH doesn't magically jump to some wild number when your FC is just BARELY over 10 ppm. I suggest you disregard the FC interference and call your pH 7.2.

Nothing in your test results would indicate algae or organics. You should probably do an OCLT to confirm that but I suspect you'll pass. So, then, your other numbers are all pretty good, leading me to think your issue is filtration. Standard good habits for a cloudy pool (assuming you pass the OCLT) are to make sure your filter is operating normally, run pump 24/7, vacuum, backwash your filter if necessary, What is your psi now? What is it when clean?

 

[Egreenwood]

@mknauss. I believe you are correct. This is an issue with the pool paint reaching the end of its life and creating a dust into the pool. I associated the increased in haziness with the days the pool was in use of the robot was running. It improved when there is less friction on the walls. I did an extra long 10 min backwash, and have not been in the pool for a few days due to the cooler water and now the pool appears to be crystal clear. Thanks for the suggestions.