Total Chlorine Too High

[GigiKay]

Hi, Everyone!

I'm Gigi. We have a 16' Intrex and switched from biguanide this year to chlorine. Biguanide was easier, but we had to switch - long story.

I super chlorinated a perfectly clean and balanced pool because we had been on vacation for the few weeks after school got out. I really regret that. It was sparkly and beautiful and blue, sigh.....

We use triclor tablets and pHree and Clear cubes, Cya is 48. The free and total chlorine were close to .40 and then I shocked it into the stratosphere. The tube was practically purple and the meter (LaMotte ColorQ 7) would only read Hi on both tests (free and total). Leslie's had sodium sulfite so we hit it with that a couple of times and brought the free chlorine down to 2.44, but the total chlorine was so high the meter still only read Hi - it will read up to 10. So we used two bags of chlorine free shock (potassium mono-suf...) and the total chlorine is now 8.56, leaving us with a 6ppm difference.

I don't know what to do (and I've surfed until my eyes hurt for an answer). Any ideas about how to bring down the total chlorine would be greatly appreciated. Even knowing that it will dissipate on its own would be a relief. I feel like the numbers are safe right now, but since they are so out of whack, I'm worried about how to use the numbers in the future.

Thanks!

Gigi

[chem geek]

Just have the pool exposed to direct sunlight and the FC should drop by 30-50% per day. Read the Pool School to learn how to properly maintain your pool including the appropriate minimum FC for your CYA level. And please get yourself a good test kit (the Taylor K-2006 or the TF100; even a Walmart HTH 5-way would be better than what you have right now, though a FAS-DPD chlorine test is more accurate and will measure high chlorine levels).

[GigiKay]

Thank you for your response. We knew the chlorine level would go down in a couple of days, but wanted to be able to swim the same day and the pool store had Clor Neutralizer, which is what we used. The FC seems to be fine (2.44), but the problem is the total chlorine, which is reading very high. I have read that the potassium monopersulfate can cause high combined chlorine readings. We used the recommended amounts for our pool.

I think it's likely that the reading is from the shock. Is the pool safe for swimming? Is there a way to neutralize the potassium monopersulfate? Will it dissipate on its own?

Thanks again,

Gigi

[chem geek]

Yes, monopersulfate (non-chlorine shock) will falsely read as Combined Chlorine (CC) unless you use an interference remover (for the Taylor test kit).

With CYA in the water, even a shock level of chlorine (an FC that is 40% of the CYA level) would still be safe for swimming. It's technically equivalent to around 0.6 ppm FC with no CYA which is less than found in most indoor pools. You just wouldn't want to drink large quantities of the pool water, but that's not something you would do anyways.