Chlorine loss

Jump to latest Follow Reply
dtrebus

dtrebus

Gold Supporter
Bronze Supporter
Apr 9, 2020
122
Claremore, OK
Pool Size
17200
Surface
Vinyl
SWG Type
CircuPool Core-55
I've read alot about normal FC loss/ day being anywhere from 1-3 ppm. I have started testing at night and adding, then testing 30 min later. Last night my FC was 8.
Tonight my pH was 7 (usually riding steady at 7.6-7.8)
FC 3
CC 0

5ppm seems like a lot. My CYA is at 50 but haven't tested it in a week (just started about a month ago, and 1/2 way through my second bottle of reagent for CYA test). I have angled return to create aeration, which should help pH,
and plan on checking CYA again. In the OK sun and it was 97 degrees today, and pool water temp was 90.

Any suggestions in trying to get less FC loss?
 
Sorry, FC tonight was 2, not 3! so 6ppm loss in one day!!!

I checked about an hour after adding chlorine, and FC is only 4, and I got a very small pink change that went away with 1 drop, so CC is 0.5.
I check from same position in pool, and go down to elbow depth, but seems that things are getting whacky. MAybe I'm just doing it wrong...maybe bleach or test chemicals are bad? Bleach dates look good, and I only got the test kit 1.5 months ago, so don't know what is going on. Help ;-)
 
Last edited:
Thanks Felipe, I will do that tomorrow. I vacuum every saturday and try to brush twice a week. Than will do OCLT.
I posted another thread about vacuums, as mine gets caught big time on divots on floor (so much that I have to run and turn off pump to break suction). I have an automatic vacuum but scared to run that and not be around if it gets stuck and possibly damage liner
 
  • Like
Reactions: Flying Tivo
Would a start of algae growth make FC levels less than predicted in pool math?
This afternoon, my tests were:
FC 2.5
cc 0
pH 7.8
CYA 50
TA 80
CH 80

I put in chlorine to get to 7ppm (per pool math), and we were swimming in it. I checked tonight and FC was 2.5
I put in bleach to get to 7ppm and an hour later, FC only read 5ppm.

Would the most probable reason be: algae, bad bleach (dates and everything looked good), poor circulation, or bad testing chemicals?

Of note, I was called on an emergency most of the day, so I plan on vacuuming and brushing (i usually do it at least once/week) tomorrow and do an OCLT...
 
This morning, my FC was 4, CC 0. I added bleach to presumed 7ppm, then I brushed and vacuumed pool. a little over an hour later, FC was 4.5. The sun is out and pool water is 90 degrees.
I don't think that short of time would degrade that much chlorine. Reading some old threads about Julian dates. this bleach I got from Atwoods is 5.25% and doesn't have a julian date, only "BB04/21/21"
So it might just be bad bleach? I am going to do the OCLT tonight and will report tomorrow.
Maybe I can use the 5.25% bleach but put in pool math to use 5% to get it a little higher. Any thoughts on that?
 
I did OCLT last night. Initial readings were: FC 5.5 CC O
This morning: FC 5 CC O. Water is crystal clear.

Of note, when I put bleach in last night b4 starting test, I put in what pool math said would raise FC to 8, but it only went to 5.5. Again, I used 5.25% bleach, but put it in as 5% on pool math.
The only things I can think of this are: bad bleach, discrepancy in estimating pool volume, or poor circulation.

I don't think even if I was a little underestimating pool volume, the predicted FC and actual would vary that much. I poured in a little bleach at different points in pool, and circulation seems good, so I can only think the bleach I got was not good (So much for trying to save money lol).

If anyone has any other suggestions or thoughts, please feel free to respond. Thank you
 
Yup, that's what my bottles say. I have 27' round with avg depth of 47.5 inches, and I just say 48. So sum is 17168g. I round down to 17k. I don't think underestimating it by less than 200 gallons would be cause. I even use 5% value for bleach on pool math, instead of 5.25% which is what bleach is supposed to be
 

Enjoying this content?

Support TFP with a donation.

Give Support
Read about hot, sunny places, raising CYA when summer is full swing, and gonna do that to. Thanks for your advice :) Do you know the concentration of the shock? I just saw it on website, but says available in select stores. Maybe I can order it and have it shipped??
 
Most pool liquid chlorine is either 10 or 12.5%, hopefully it's one of those. $1.99 a gallon is a pretty good price!
Perhaps your bleach was exposed to some excessive heat sitting in the trailer before delivery?
 
dtrebus said:
Read about hot, sunny places, raising CYA when summer is full swing, and gonna do that to. Thanks for your advice :) Do you know the concentration of the shock? I just saw it on website, but says available in select stores. Maybe I can order it and have it shipped??
Click to expand...
I used to raise mine to 60 through the hot months. Atwood’s pool shock runs either $1.99 or $2.49 a gallon, they run it at $1.99 a lot. It is 10% and I used to go through 42 cases a season. I was very happy with it. We switched to a SWG this year otherwise I would still be using it.
 
  • Like
Reactions: BadDogPSD
Today, my tests were:
FC 5
CC 0
pH 8
CYA 60
TA 90
CH 80

I solved the mystery of the bleach (thought it was bad or reading errors) but I discovered that the atwood's bleach was 3%! bleach.jpg
 
  • Wow
Reactions: Flying Tivo

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply