Chlorine fall/shock

For 10 days or so, I had kept my pool at shock level for more than a week to kill what appeared to be white mold.

It is gone, but in the process, my chlorine level had soared to 27. Long story short, kit I was using was way off. I have Ben's P234 now and it has recorded these levels of chlorine:
4/29: 27
5/1: 18.5
5/3: 12.5

Other #s are fine and have been. CYA is 20.

Question: Today (5/3), I had a cc of .5. Now, to get rid of that, you must shock, correct? Should I shock with such high reading? According to best guess chart, 12.5 would be right at shock level now.

Thanks in advance. Trying to stay ahead of my water.

Most folks accept that anything 0.5 and below for CC is okay. I don't have Ben's kit (on the way), so I can't say for certain.

Thanks for the response. I will keep monitoring it. Love the new kit, by the way.

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Originally Posted by GolfTop

Question: Today (5/3), I had a cc of .5. Now, to get rid of that, you must shock, correct? Should I shock with such high reading? According to best guess chart, 12.5 would be right at shock level now.

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Actually, when you test to the 10ml level on the sample tube, a reading of 0.5 simply indicates that your CC is not absolutely zero. Put another way, your CC is "0.0 < CC < 0.5", if you can follow that.

If you really have to know how much CC there is, test from the 25ml mark. Then, the first increment is "0.0 < CC < 0.2".

But, really, most of the time, I wish people wouldn't test for CC. Shocking does NOT work to remove CC's most of the time, nor do most of the other chemical rain-dances recommended by pool stores. If you simply operate the pool correctly, and maintain consistently chlorinated, algae free water, and don't add pool store goop, your pool will become -- and remain -- practically CC free.

If you test for them, you will see CC spikes after parties, especially if the parties include members of the "leaky bladder" set or the "mommie, I have to go NOW!" set, or really sweaty big guys. Shocking before or after heavy bather loads is a good idea.

But it's better to treat your pool properly, than to pay too much attention to CC's. The only time when CC levels really *need* to be considered is when you are deliberately using monochloramine (via the Yellow OUT or clone route), or have dosed your pool with some seriously messed-up pool store goo, and have to clean it up, or are cleaning up a bad CYA biodegradation mess in the spring time. The rest of the time, you'd be better off not testing.

Heck, I may even *hide* the CHL #3 (R-0003) in the PS235! :rolleyes:

Ben

"PoolDoc"

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Originally Posted by PoolDoc

or really sweaty big guys.

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Hey, I resemble that comment!
(Nothing I like better than mowing the lawn on a hot summer day, then falling in the deep end. But it's my pool!)

C.

Learn something every day. Thanks Ben.

I've learned to shun the pool store like it was my ex-wife.