Lost 3.5ppm of FC in 2 days/Is This Normal???

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Mendy48

Mendy48

Bronze Supporter
Apr 27, 2018
1,006
Midland, MI
Lost 3.5 of FC since May 6th... just two days ago. Is this normal. Basically, it went from 4 - 1.5 in two days. I just added 56oz of bleach to get it back to 4ppm. I'll wait for an hour or so to retest. But wow...Cl doesn't last that long huh....

With that said, I'm going through bleach like crazy. Anyhow, I just wanted to know if this type of FC lost was normal.
 
What is your CYA level and pool conditions/temps? That is very normal if enough CYA in pool and FC to match it at top of range. I lose about that much daily in Texas with CYA at 50 0r 60.
 
I've been running my pool in the Midwest with CYA at 40 and see chlorine usage about that rate, sometimes more. This is normal, which is why adding chlorine daily is necessary no matter what system you are using. I'm experimenting with a higher CYA this year to see if it makes a difference. Going to aim for 50 to 60, which I'm hoping will be enough since I am not in TX. But I do have full sun on my pool all day.
 
e,

Most pools use between 2 and 4 ppm of FC per day...

If anything, your pool is on the low end... Just one of the reasons that a lot of members are going with Saltwater Chlorine Generator systems...

Just to make sure, I recommend that you run an Overnight Chlorine Loss Test (OCLT). Here is how... Overnight Chlorine Loss Test

The OCLT will tell you if your FC loss is normal, or if there is something in the water consuming your FC...

Thanks for posting,

Jim R
 
Minimum FC level for CYA 40 is 3 - FC should never go below 3. Target range is 5-7. Pool School - Chlorine / CYA Chart

If you are only checking FC every other day, dose for the high end or maybe a point or two higher.

I recommend you perform an Overnight Chlorine Loss Test to ensure you don't have a nascent algae bloom.
 
I have a CYA of ~44 with a 22K gallon, in ground plaster pool, and have been adding about 45oz / day. This is my first summer with the pool, so not really too sure what to expect.

I have also been adding MA (31.45%) to keep my pH down, maybe about 8oz a few times per week.

I've been using the "Pool Math" app to help me out.

Is CYA=44 a bit too low? Any recommendations?
Also, what should my target pH be? The app has 7.4 as the target.
Last question, is it normal for the pH to rise when adding CL?

Here are my latest test results:
FC 3.4
pH 7.5
TA 80
CH 280
CYA 44
Temp 72F

thanks!
Curt
 
Your pool is not consuming as much fc as you thought...4 - 1.5 = 2.5, not 3.5.

You also don't mention how much sun your pool gets per day, but 1.25ppm fc loss, per day, is not unusual at all. If you don't want to dose as often, when servicing, just add enough to take it up to the high end of the range. Never let it go below the low end and you should be ok.
 
Thanks..yeah!!! my math skills are not up to par ...LOL

My pool has full sun, so I guess the FC lost is normal. yeah! I really don't want to dose as often, when servicing, so I'm going to add enough to take it up to the high end of the range.




SemperFly said:
Your pool is not consuming as much fc as you thought...4 - 1.5 = 2.5, not 3.5.

You also don't mention how much sun your pool gets per day, but 1.25ppm fc loss, per day, is not unusual at all. If you don't want to dose as often, when servicing, just add enough to take it up to the high end of the range. Never let it go below the low end and you should be ok.
Click to expand...

- - - Updated - - -

Just got my pool; so I never thought of going with a Saltwater Chlorine Generator. I probably should have. However, I did run an OCLT two days ago and I only lost 1ppm of FC, which is good. I followed the directions on Overnight Chlorine Loss Test

Thanks for the reply.:)

Jimrahbe said:
e,

Most pools use between 2 and 4 ppm of FC per day...

If anything, your pool is on the low end... Just one of the reasons that a lot of members are going with Saltwater Chlorine Generator systems...

Just to make sure, I recommend that you run an Overnight Chlorine Loss Test (OCLT). Here is how... Overnight Chlorine Loss Test

The OCLT will tell you if your FC loss is normal, or if there is something in the water consuming your FC...

Thanks for posting,

Jim R
Click to expand...

- - - Updated - - -

I'm going to add more Chlorine, because my target was a 4 not a 5. I'll check my FC before adding. I ran an OCLT a couple of days ago...I may re-run it starting tonight?



proavia said:
Minimum FC level for CYA 40 is 3 - FC should never go below 3. Target range is 5-7. Pool School - Chlorine / CYA Chart

If you are only checking FC every other day, dose for the high end or maybe a point or two higher.

I recommend you perform an Overnight Chlorine Loss Test to ensure you don't have a nascent algae bloom.
Click to expand...

- - - Updated - - -

What type of pool doing you have...

Can you add this information on your signature page...

Are you using TF-100 to test your sample?


scottdog123 said:
I have a CYA of ~44 with a 22K gallon, in ground plaster pool, and have been adding about 45oz / day. This is my first summer with the pool, so not really too sure what to expect.

I have also been adding MA (31.45%) to keep my pH down, maybe about 8oz a few times per week.

I've been using the "Pool Math" app to help me out.

Is CYA=44 a bit too low? Any recommendations?
Also, what should my target pH be? The app has 7.4 as the target.
Last question, is it normal for the pH to rise when adding CL?

Here are my latest test results:
FC 3.4
pH 7.5
TA 80
CH 280
CYA 44
Temp 72F

thanks!
Curt
Click to expand...
 

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Just tested my pool. I deliberately add a certain amount of chlorine to see if I'll get close to 4.5 and I did. TF-100 is pretty accurate.
FC 4.5
pH 7.2
TA 180 (I'm not sure how to bring this down a bit. Or is it ok the way it is?)
CYA 40
Temp 83F (yup! the heater is on and I'm going swimming soon. Hate swimming in a very cold pool. I never seem to get in the pool when the temperature is low.)

I'm going to run an OCLT later on this evening... I should have some results tomorrow morning.
 
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