Did I buy bad bleach?

May 17, 2010
9
First, I want to say that I am a new member, but have been lurking here for several years. You all have taught me the BBB method and I love it! Thank you. I just opened up my pool and was pleased to find it quite clean. I bought some bleach from Walmart to shock the pool, the brand is "Good Value", I checked and it is 6%. I put enough bleach to bring the FC up to 18 based on the Pool Calculator but when I tested the water 2 hours later the FC was only 7 and the CC was 0 (clear) based on my handy Taylor Test Kit T-100. I got the same result an hour later. Its a rainy, cloudy day so the sun should not play a factor.. Is there any way to check whether Bleach is still "fresh"? Also, how long does the chemicals in the Test Kit last, mine is about 3 years old. I would hate to have to replace all the chemicals if it is not necessary. Any thoughts?
 
What is your CYA level? If it is low, the sun can burn off the chlorine pretty quick.

Or you have have some algae lurking that you were not aware of.

Or there are a lot of organics somewhere in the system?
 
I do not know what the CYA level is, at the end of last year it was around 40 and this year I had to replace about 1/4 of the water. No sun today, cloudy and rainy. If I had a lot of organics wouldn't I have a CC level? It just seems like a fast loss after only 2 hours and the water was really clear. I do plan on bringing up the CYA after I finish shocking since the sun will not be out for another day or two. I thought if I kept it down I would not have to use as much bleach to shock.
 
Though you might think that it has gone from 40 to maybe 30 based on the water replacement, rains may have replaced water also if the pool overflowed through the overflow grate. Here in Houston area we typically have wet winters and my CYA was 22 upon testing in May, last measured at 45 in January. I will admit to having left the water running while refilling the pool but that was maybe 2' of water the rest was due to rain.
 
Yes, I agree, my CYA is lower, but at this point would that have much of a difference in the rate of FC loss if the sun is not shining? I do have 8 lbs of Conditioner I was planning on putting in,(maybe even more to bring it up to around 70) but with out the sun for a few days I thought I should wait and take advantage of the need for lower chlorine levels. Am I wrong? Does it sound like the bleach I bought and the test kit could be accurate? Because I will have to go back out and buy more to restock and I only paid $2.54 for the large jugs and I want to stock up.
 
My FC has now dropped to 11. Clearly I have organics that are eating up my chlorine. I calculated the rate of loss and it seems to me that if the bleach was "bad" then I would have had a larger % of loss after I added the second dose. My calculations are as follows, let me know if anyone finds an error. Otherwise I will assume the bleach and my test kit chemicals are fine.

I started out putting in 910 oz. in this should have brought my FC to 22
2 hours later I tested FC 7 (68% loss)
1 hour later I tested FC 7 (no change after an hour)
I then added 728 oz. to bring the FC up to 24
1 hour later I tested FC 15 (38% loss)
Almost 2 hours later I tested FC 11 (27% loss)
 
I thought the same thing Richard, thats why I went back 1 hour later and retested, but I got the same reading. In the 5 years that I have had this pool, I have never seen a loss in FC this fast and I have had some real messy openings. This year the water looked really good. I guess thats why we invest in these test kits and not rely on sight/smell.
 

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