Chlorine Locked?

We're doing the experiment above. We put the 2 gallons pool water in a clean bucket, waited one hour. Tested 0 fcl, 7.5 tcl, 7.5 ccl. Put ph up, mix, put hydrogen peroxide, mix, waited 1 hour, measured, fcl 0, tcl 5, ccl 5. We'll see what we get tonight after waiting 8 hours then tomorrow night after 24 hours.
Also, we're going to change the sand ( I had told my husband the other day that I thought maybe that was part of the problem since all of that junk was in the filter). I'm glad to know I'm not totally alone in my thinking! I'm also going to get the filter socks. I never heard of them before.
I'll post the results.

Skimmer socks are also called "filter savers". Brand doesn't matter.

I find bleach, washing soda and borax all at the local supermarket, which is far closer than the nearest WalMart.

Carl

Tonight's results on the bucket of pool water were:
fcl 0
ccl 0
I did the test twice and it was totally clear. I'll check again at 9:00 pm tomorrow night.
After checking tomorrow night, Chem geek said to add 1/4 tsp. bleach at a time until fc registers again and make sure that cc doesn't return (hopefully). How long would we wait between adding each 1/4 tsp. of bleach?

So far, so good. It looks like it does reduce CC taking somewhere between 1 and 8 hours to do so. After you start adding bleach after measuring tomorrow night, you can measure within an hour and then add more bleach. Repeat until you start to measure FC that should then hold and we'll see if the CC returns or not.

If the CC returns after adding bleach, then that would mean the hydrogen peroxide was just acting as a reducing agent to get rid of CC, but then adding a chlorine oxidizer again would recreate CC. If instead the CC doesn't return after adding bleach, then that means the hydrogen peroxide oxidizes the CC to truly get rid of it. Let's keep our fingers crossed that the latter is what is happening.

Quote:

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Originally Posted by chem geek

So
If the CC returns after adding bleach, then that would mean the hydrogen peroxide was just acting as a reducing agent to get rid of CC, but then adding a chlorine oxidizer again would recreate CC. If instead the CC doesn't return after adding bleach, then that means the hydrogen peroxide oxidizes the CC to truly get rid of it. Let's keep our fingers crossed that the latter is what is happening.

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Also, if the CC returns but at a lower level then the process is working but might need to be repeated.

Here are the readings tonight.
7:00 pm
fcl 0
tcl 0
ccl 0
added 1/4 tsp. bleach

8:00 pm
fcl 0
tcl 0
ccl 0
added 1/4 tsp. bleach

9:00 pm
fcl 2.5
tcl 2.5
ccl 0
added 1/4 tsp. bleach

10:00 pm
fcl 4
tcl 4
ccl 0
added 1/4 tsp. bleach
That's going to be it until tomorrow night after work.

Oh my gosh! This might actually be working!!! This is great news. 1/4 teaspoon of 6% bleach in 2 gallons would normally raise the FC by 10 ppm so I'm not sure what's consuming so much chlorine after you start measuring it. The reaction with the remaining hydrogen peroxide should be fast which explains the first couple of hours of readings, but after that I would have expected chlorine addition at 9 PM to register more like 12.5 ppm at 10 PM. At least you aren't getting CC readings.

Tonights readings:
6:30 pm
fcl 2.5
tcl 2.5
ccl 0

7:30
fcl 7.5
tcl 7.5
ccl 0

8:30
fcl 10
tcl 10
ccl 0

9:30
fcl 15
tcl 15
ccl 0

Most of these tests I performed 2 times to double check
No combined chlorine in any of the checks!
So what now?

Well now you can use sodium percarbonate in your pool. I think you just got the pH Up and hydrogen peroxide, neither of which will be in sufficient quantities for your pool. So you'll have to buy sodium percarbonate. You can get it at The Chemistry Store. As for how much to get for your 15,000 gallon pool, if you want to you could redo your experiment with a half-dose or even a quarter-dose. That might save you money. The dosage I had you do was roughly 1 pound per 1000 gallons. That would be 15 pounds or about $40 worth of sodium percarbonate. I suspect it won't take that much. If you redo the bucket experiment (you don't need to wait as long now that we know that the CC is eliminated in less than 8 hours), then that could save you money if you find you only need half or one-quarter as much -- up to you.

Richard, can't she just buy "washing soda" at Walmart and "BaquaShok" at her pool store?