Am I reading chlorine right?

[fhorta]

Hey all. Just wanted to run this through really quick make sure my process is right. So, I was at 12ppm chlorine at 6pm. Added 100 Oz and expected chl to go up to at least 16ppm (usually. 16 to 20 Oz raises chl by 1ppm). I waited about 45 mins and tested chl. I was shocked, no pun, that result waS only 14ppm; only went up by 2ppm?? So, added another 100 Oz and this time I tested only about 5 mins after adding and brushing. This time it was at 19.5, maybe 20ppm, going up by 6ppm this time?? I guess chl level starts going down almost instantly after adding? Feedback, experience, comments? BTW, I'm having bit of algae trying to bloom is why doing all this.

Also, did the combined chl test and sample did not turn pink..as I recall, it never does everything I tested it which is why I stopped buying it. Could it be that when chl is so high that that test is null?

 

[DrewLG]

Could it be that when chl is so high that that test is null?

No.

What concentration is the chlorine you're adding? How old is it?

 

[fhorta]

It's supposed to be 12.5%. Just bought today.

 

[DrewLG]

If your pool is really 24,000 gallons, 100 ounces of 12.5% LC should raise FC by 4 ppm. So 200 ounces should have raised FC by 8 ppm, which is what you measured. The only problem is that you didn't wait very long after adding the second 100 ounces, so it's possible that you tested before the chlorine had a chance to fully mix with your pool water.

If you feel like measuring again now, you'll get a better idea of what the fully mixed FC concentration actually is. And you'll have a "before" measurement that you can compare to an "after" measurement taken early tomorrow morning for the Overnight Chlorine Loss Test.

 

[fhorta]

I measured again, about another 5 minutes after last meaurelast night. This time I got 17.5ppm; maybe a more accurate one indicating a raise of 3.5ppm from 14ppm. But I'm still baffled at the first 100 only raising by 2ppm. Unless in 45 mins it lost 2ppm? I'm about to take chl this am see where I'm at.

 

[Bperry]

I measured again, about another 5 minutes after last meaurelast night. This time I got 17.5ppm; maybe a more accurate one indicating a raise of 3.5ppm from 14ppm. But I'm still baffled at the first 100 only raising by 2ppm. Unless in 45 mins it lost 2ppm? I'm about to take chl this am see where I'm at.

If you have algae, that will be consuming chlorine. And realize the test has a tolerance of +/- 0.5ppm, and there’s lots of other variables like quantity of water, age of chlorine, etc that’ll all affect the results.

 

[fhorta]

Ok, thanks. So this am's results is 14.5ppm. Lost 3ppm overnight.However, for first time in this sequence water looking more mirror like clarity as opposed to that lack luster clarity I was seeing. I think I will be slamming closer to 18 to 20 ppm instead of the 16. Also, did the combined chl test and still nothing. I left sample alone for about 5 mins and when I came back and about to throw it out I noticed it was pink at the base, not the water though. Is this a valid test? I did throw in 0871 until clear again, took about 4 drops.

 

[clambert1273]

Ok, thanks. So this am's results is 14.5ppm. Lost 3ppm overnight.However, for first time in this sequence water looking more mirror like clarity as opposed to that lack luster clarity I was seeing. I think I will be slamming closer to 18 to 20 ppm instead of the 16. Also, did the combined chl test and still nothing. I left sample alone for about 5 mins and when I came back and about to throw it out I noticed it was pink at the base, not the water though. Is this a valid test? I did throw in 0871 until clear again, took about 4 drops.

Yes, if you leave it sitting it will turn pink again. Results are during active testing

 

[Bperry]

Ok, thanks. So this am's results is 14.5ppm. Lost 3ppm overnight.However, for first time in this sequence water looking more mirror like clarity as opposed to that lack luster clarity I was seeing. I think I will be slamming closer to 18 to 20 ppm instead of the 16. Also, did the combined chl test and still nothing. I left sample alone for about 5 mins and when I came back and about to throw it out I noticed it was pink at the base, not the water though. Is this a valid test? I did throw in 0871 until clear again, took about 4 drops.

Don’t dose about the SLAM level for your CYA. You risk damaging equipment and wasting chlorine as it burns off much faster as the levels increase. Just follow the process.

 

[fhorta]

Yea, i'm just not understanding why if it is clear there is something in water which is consuming chl, why my comnbined chl is always showing 0.

 

[reggiehammond]

Algae is invisible, consuming chlorine, for quite a while before colony sizes get large enough to be visible in terms of color or clarity issues.

Also call free chlorine or added chlorine by FC to make it obvious what you’re talking about.

 

[Bperry]

Yea, i'm just not understanding why if it is clear there is something in water which is consuming chl, why my comnbined chl is always showing 0.

algae doesn’t become visible until it’s too late. It starts out not being very visible and once it does its close to swamp time.

 

[fhorta]

Ok. So tonight added 160 Oz and raised from 11ppm to 14ppm. I thought it would take it to 16ppm at least. I waited Bout 15 to 20 mins to measure added chlorine. I added another 32 Oz, waited about 10 Mins, went to 15ppm; still not desired 16. Added another 32, tested after 5 mins and now at 18.5ppm, a difference of 3.5ppm. I don't know. In conclusion, if test within 5 mins of added chlorine, I get higher result. If I wait 10 to 15 mins, much more 45 minutes, my result is much lower.

 

[IceShadow]

Yea, i'm just not understanding why if it is clear there is something in water which is consuming chl, why my comnbined chl is always showing 0.

CCs indicate a problem, but there are plenty of ways to get algae and never have it show as CCs. Lack of CCs do not indicate healthy water. It’s just one data point. You can have 0 CCs and still have algae.

 

[IceShadow]

CC - Further Reading

www.troublefreepool.com

 

[fhorta]

Ok, that makes sense. I am now losing 1.5, maybe 1 ppm chlorine overnight. I put in 2 gallons last night of 12.5%. Waited for about an hour before retesting after sundown and raised from 11 to 17ppm. This morning between 15.5 and 16ppm. It's taking over 40 Oz of chlorine to raise by one ppm. Before it only needed 20 Oz.