Please post your average daily FC loss % per CYA

Jump to latest Follow Reply
Speedo

Speedo

0
LifeTime Supporter
May 4, 2011
634
I've been thinking about this and it appears I was looking at the CYA test wrong. After reviewing Taylor's website and seeing the image I think my actual CYA level is 40 when I was treating it as 60. Maybe I was afraid I would be wrong and made sure the dot was a little too visible, thus giving me a higher reading.

Either way I add a little buffer (treating it as +5 ppm cya). When I thought it was 60 I was targeting 7.5 ppm FC and now that I think it's 40, I will target 5.5 (which would be 45ppm cya).

So, here is what I want to compare (please post):


FC you're targeting .... CYA level .... ppm FC loss (sunny day) .... avg % daily loss
------------------------------------------
7.5 .... 60 (probably 40) .... 5 .... 40%

My daily loss was averaging 5ppm/day (on a sunny day) which I would add to the 7.5 giving me 12.5, (5ppm loss/day)/(12.5 FC after adding 5ppm to account for tomorrow's loss) = 0.4, 40%

Tomorrow is predicted to be sunny, so I should be able to take my solar cover off and determine my usage at the proper target FC soon.

I'm interested to see what everyone's numbers are.
 
It might be interesting for you to get the cya reference solution available at tftestkits.net and see what you get for cya with that.

The 40% FC loss is not unusual and might go down just a little more if you push the cya level up to 50 ppm...certainly not necessary, but might save a little chlorine.

I can not tell you what I experience, since I use a swg.
 
Speedo said:
Either way I add a little buffer (treating it as +5 ppm cya). When I thought it was 60 I was targeting 7.5 ppm FC and now that I think it's 40, I will target 5.5 (which would be 45ppm cya).
Click to expand...

Since the CYA test has a +/- 15ppm accuracy rating - I asked about "buffering" as you say. I was told the chart has enough safety margin to account for the +/- 15ppm.


Speedo said:
So, here is what I want to compare (please post):

FC you're targeting .... CYA level .... ppm FC loss (sunny day) .... avg % daily loss
------------------------------------------
7.5 .... 60 (probably 40) .... 5 .... 40%

My daily loss was averaging 5ppm/day (on a sunny day) which I would add to the 7.5 giving me 12.5, (5ppm loss/day)/(12.5 FC after adding 5ppm to account for tomorrow's loss) = 0.4, 40%
Click to expand...

Your definition of target is confusing me. Is target what you are trying to reach at the start of the day - that's what I would mean if I said I have a target FC level of 8-9 for example. The way I read this however, you seem to mean this is your MINIMUM you want to reach during the day. So if I understan you are raising to 12.5 FC and then allowing that to drop during the day to 7.5 (5ppm loss).

If I were answering your question with this logic I would say:

FC you're targeting .... CYA level .... ppm FC loss (sunny day) .... avg % daily loss
------------------------------------------
5.5 .... 55.... 3.2-3.7 .... %40 (between 36% - 42%)
 
linen said:
It might be interesting for you to get the cya reference solution available at tftestkits.net and see what you get for cya with that.

The 40% FC loss is not unusual and might go down just a little more if you push the cya level up to 50 ppm...certainly not necessary, but might save a little chlorine.

I can not tell you what I experience, since I use a swg.
Click to expand...
Are you talking about the CYA "view tube" ? I'll definitely get this when I place my next order. I'm going to keep my target at 5.5 for the remainder of this season and see what my CYA is when I open next spring (since I'm sure I will be adding some). I'll target a CYA of 40 and if the sunny days start up and I'm losing too much FC I will bump cya a bit.

UnderWaterVanya said:
Since the CYA test has a +/- 15ppm accuracy rating - I asked about "buffering" as you say. I was told the chart has enough safety margin to account for the +/- 15ppm.

Your definition of target is confusing me. Is target what you are trying to reach at the start of the day - that's what I would mean if I said I have a target FC level of 8-9 for example. The way I read this however, you seem to mean this is your MINIMUM you want to reach during the day. So if I understan you are raising to 12.5 FC and then allowing that to drop during the day to 7.5 (5ppm loss).

If I were answering your question with this logic I would say:

FC you're targeting .... CYA level .... ppm FC loss (sunny day) .... avg % daily loss
------------------------------------------
5.5 .... 55.... 3.2-3.7 .... %40 (between 36% - 42%)
Click to expand...
I forgot about the accuracy rating, that's a good thing to remember. You are correct in assuming 7.5 is my minimum. As it's listed on the chart I would assume someone following 100% would try to make the maximum their peak and never go below the minimum. I seem to give it a bit of overkill, I take the target and add a .5 buffer to calculate my minimum. I do allow it to drop to 7.5 the next day after upping to 12.5 FC at night.

I'm going to start letting it drop to 5.5 and probably take it up to 9 on nights before a sunny day w/o the cover. On covered days I had observed a usage of around 1.7ppm/day, I'm assuming that might be a bit lower with a minimum of 5.5 (vs 7.5). I will test and see how it goes.
 
The CYA / Chlorine Chart has no max only min and target. The poolcalculator website has a range with a min/max but the max is kinda funny given that it is considerably below the shock value and you're really OK as long as under shock...

If I have a higher than normal bather load I tend to give it an extra slap in the rump but otherwise I have been doing well with this model.
 
That's funny, I completely blanked out... I knew that the 3rd column was shock value and min FC / target are the other two. I'll admit though I rarely have to look at it :goodjob:

Even with my additional 5 ppm, if I have a lot of people swimming I will bump it a tad higher too. I still think it would be interesting for other people to post their levels, but at least I've come to the conclusion that I will be just fine using 5.5 instead of 7.5. And also I will purchase the CYA tube to see if that makes it any easier.

I think last year when I thought my CYA was 95, it was likely a bit lower. I probably tried to cover the dot almost completely, in the picture I can still tell the dot is there, as I could in person - when I came up with 40. I'm willing to bet I've targeted a FC 2ppm higher than needed since the beginning of last summer. Oh well.
 
Speedo said:
linen said:
It might be interesting for you to get the cya reference solution available at tftestkits.net and see what you get for cya with that.

Are you talking about the CYA "view tube" ? I'll definitely get this when I place my next order. I'm going to keep my target at 5.5 for the remainder of this season and see what my CYA is when I open next spring (since I'm sure I will be adding some). I'll target a CYA of 40 and if the sunny days start up and I'm losing too much FC I will bump cya a bit.
Click to expand...
Click to expand...

I don't think he is. The CYA Reference Solution is a premade solution with water and CYA so you can verify that your test process is giving you the results expected. Essentially, you use this rather than pool water and make sure that your test agrees and comes up with the same value as the reference premixed solution.

TFTestkits sells the R-7065 50ppm CYA solution on their site: http://tftestkits.net/R-7065-CYA-Standa ... n-p34.html
 
linen said:
Speedo said:
Are you talking about the CYA "view tube" ?
Click to expand...
No I'm talking about this: http://tftestkits.net/R-7065-CYA-Standard-Solution-p34.html It is a solution that gives you 50 ppm cya, to test your technique.
Click to expand...
I never noticed that, AWESOME product! I will definitely try this to verify my reading.

fast1971chevelle said:
I lose 2 ppm fc and my cya is 50 and my pool sees full sun 12 hours a day.....MIKE
Click to expand...
Do you use 6 as your target? Taking it up to 8ppm when you dose?


6 .... 50 .... 2 .... 25%
 

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