Testing the percentage of sodium hypochlorite

No. I’m sure I’ve seen your question asked before and thought the answer would be in the wiki. A google search came up with the recipe that starts with 0.1ml which could be a bit tricky to measure out. Matt’s method would be easier and I’ve asked ajw22 if he could put it in the wiki for future reference. We’re all good. :)
My search did not end up with a result that I could use so that’s why I brought up the question. Obviously I’m not a normal contributor to the board but I thought it was a fair question
 
My search did not end up with a result that I could use so that’s why I brought up the question. Obviously I’m not a normal contributor to the board but I thought it was a fair question

It’s good question and I’m glad you asked. And now you’ve helped us put the info into the wiki for everyone to use. I always seem to have a jug that’s been sitting around over winter and I‘ve just guessed at it being about 1/2 strength but now I can test it and be a bit more accurate.

@JoyfulNoise just checking. If 1ml is a bit small, 10ml in 1L twice would work too, although I think 10ml in 990ml twice is a tad more accurate?
 
It’s good question and I’m glad you asked. And now you’ve helped us put the info into the wiki for everyone to use. I always seem to have a jug that’s been sitting around over winter and I‘ve just guessed at it being about 1/2 strength but now I can test it and be a bit more accurate.

@JoyfulNoise just checking. If 1ml is a bit small, 10ml in 1L twice would work too, although I think 10ml in 990ml twice is a tad more accurate?

The proper way to make a dilution is to use a well calibrated flask, fill it 2/3rds with distilled water, add the volume of chemical you are diluting and then fill the flask up to mark with DI water. Then swirl for 30secs or so to mix. Erlenmeyer flasks are the appropriate glassware for the task. I chose 1mL and 100mL because working in 100mL volumes is easy to do by hand. Trying to swirl and mix a liter of solution is not that easy …
 
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So using distilled water the result was 14%. I’m using hospital grade ml canisters and I was as accurate as I could be. I’m sure it’s not 14% bleach. But I would say, based off this test, it is not lacking as I thought.
I have used this brand for several years and it always stays true to ppm when adding the asked for ounces until these two cases of Julian date. So I’m not sure what I can account this to.

Any ideas?
 
So using distilled water the result was 14%. I’m using hospital grade ml canisters and I was as accurate as I could be. I’m sure it’s not 14% bleach. But I would say, based off this test, it is not lacking as I thought.
I have used this brand for several years and it always stays true to ppm when adding the asked for ounces until these two cases of Julian date. So I’m not sure what I can account this to.

Any ideas?

Like I said, that particular test is really a rough estimate. I trust your dilutions and measures.

i think the chlorinating liquid is fine.

Have you run an overnight chlorine loss test to make sure there’s nothing in the water consuming chlorine?
 
Like I said, that particular test is really a rough estimate. I trust your dilutions and measures.

i think the chlorinating liquid is fine.

Have you run an overnight chlorine loss test to make sure there’s nothing in the water consuming chlorine?
Yes, I always use less than 1 overnight. I haven’t had a trace of combined chorine for years (since I bought the house). It has been extremely full sun here for about the same time I have had this batch of bleach so maybe that is it. I also use a solar cover though. It doesn’t make sense to me because I really follow the chemistry very closely.
 
Yes, I always use less than 1 overnight. I haven’t had a trace of combined chorine for years (since I bought the house). It has been extremely full sun here for about the same time I have had this batch of bleach so maybe that is it. I also use a solar cover though. It doesn’t make sense to me because I really follow the chemistry very closely.
I should add that my psi has been acting very strange this year. In years past I have also run between 8-10 between backwash. This year it has been all over the place and not by time of day or anything. But it will go from 2-8 at any point. I’ve done everything I know to do to figure out that issue. But I didn’t feel it made any difference in the chorine usage.

Also, water pressure from the returns are normal nothing else seems amiss.
 
Your pressure issues may just be that tIme for a new one, they don’t last forever, but they are relatively inexpensive and easy to replace.

The FC discrepancy may still be due to a little algae hiding without being easily seen. Pool covers are prime candidate, particularly the bubble type ones that generate condensation under the cover and provide a nice little area for limited growth under normal conditions but maybe just enough to affect FC demand. Do clean and sanitize your cover?
 
Obviously I’m not a normal contributor to the board but I thought it was a fair question
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Your pressure issues may just be that tIme for a new one, they don’t last forever, but they are relatively inexpensive and easy to replace.

The FC discrepancy may still be due to a little algae hiding without being easily seen. Pool covers are prime candidate, particularly the bubble type ones that generate condensation under the cover and provide a nice little area for limited growth under normal conditions but maybe just enough to affect FC demand. Do clean and sanitize your cover?
I normally have to had about 40 ounces of 10% each day with the cover off. Sometimes with the cover on I ad nothing.

I do have a new cover this year which is not as thick. I which is 8 instead of 12 I believe we had in the past. But even before having a cover I used about 40 per day no matter what.

Wouldn’t the slight bit of algae show up in the combined chlorine test?
 
.Wouldn’t the slight bit of algae show up in the combined chlorine test?

This is a common misconception. Algae mostly does not create CCs.

CCs are mostly created by compounds like ammonia where the nitrogen is in the -3 state. For ammonia, you get combination and oxidation. So, the CCs eventually go away, especially in sunlight where UV photons knock loose electrons from the nitrogen and make it easier for the chlorine to take them.

Read CC - Further Reading
 
This is a common misconception. Algae mostly does not create CCs.

CCs are mostly created by compounds like ammonia where the nitrogen is in the -3 state. For ammonia, you get combination and oxidation. So, the CCs eventually go away, especially in sunlight where UV photons knock loose electrons from the nitrogen and make it easier for the chlorine to take them.

Read CC - Further Reading
How should I proceed then?

I have described that I do not lose overnight and the water is crystal clear.

What is my process from here?
 
This is a common misconception. Algae mostly does not create CCs.

CCs are mostly created by compounds like ammonia where the nitrogen is in the -3 state. For ammonia, you get combination and oxidation. So, the CCs eventually go away, especially in sunlight where UV photons knock loose electrons from the nitrogen and make it easier for the chlorine to take them.

Read CC - Further Reading
What is the purpose of the CC test?
 
What is the purpose of the CC test?
CC is one of a few indicators that pool water may be unsanitary.

Cloudy water, excessive chlorine consumption, CCs are all warning signals just like canaries in a coal mine.
 
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