Thoughts On CYA Level VS FC

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taylormade

Active member
May 11, 2017
39
Hamilton, Ontario
Hi, I have been struggling to clear up the cloudiness in my pool (I think it's because of the high CYA) for 3 weeks now. I opened to a green, swampy mess and am getting very close as my OCLT result is only 0.35. Problem is, I added too much CYA and my reading is 95/105. I see it is suggested to have the CYA at a level of 70 for my SWG and keep the FC between 5 and 10. I also see with the Pool Math App that with my current CYA reading of 95/105 that a FC reading of 7 is suggested.....which is still within the 5/10 that is suggested if my CYA was 70. I was just going to go drain a bunch from my pool to get the CYA in check but wonder if it's a waste of time/water/money....also wonder if keeping the FC at 7 (which seems high and maybe uncomfortable for swimming) is a good idea or a normal thing. This will bug me until I get opinions from people with more experience than me, hence my post. So should I remove water and get the CYA at a level of 70 so I can keep my FC requirements down to 5-ish, or should I leave things alone with my high CYA level of 95/105 and run with a FC closer to 7? Thanks

Here are my readings

CY-100
PH-7.1 (going to aerate soon)
AL- 95/103 (going to add some decreaser)
CA- 85 (dunno, should I add some increaser)
CL- 5
CC- 0.25
CU- 0.07
PO4- 0.24
 
Are you testing for those numbers yourself ? The CYA test is logarithmic, you cannot 'interpolate' between the marks and come up with 95 or 105.

If your CYA is 100, your absolute minimum FC number should be 5. Better if it was 7.
My pool CYA is 80 right now, and the FC yesterday when Grandson and I was swimming was 11...no issues at all.
Chlorine is not what irritates your eyes etc, it's the Chloramines, and PH.
Keeping your FC so close to the minimum is just inviting algae - and you already know how much hassle that will be.
I'd aim closer to the higher end of the target scale, not the minimum. Having your FC at 11/12/13 will not cause you any issues.
 
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SJPoe said:
Are you testing for those numbers yourself ? The CYA test is logarithmic, you cannot 'interpolate' between the marks and come up with 95 or 105.

If your CYA is 100, your absolute minimum FC number should be 5. Better if it was 7.
My pool CYA is 80 right now, and the FC yesterday when Grandson and I was swimming was 11...no issues at all.
Chlorine is not what irritates your eyes etc, it's the Chloramines, and PH.
Keeping your FC so close to the minimum is just inviting algae - and you already know how much hassle that will be.
I'd aim closer to the higher end of the target scale, not the minimum. Having your FC at 11/12/13 will not cause you any issues.
Click to expand...
Hi and thanks for the reply, I am testing myself and use a Pool Exact EZ Photometer in combination with my Taylor CK-2005 that I continue to use for CYA testing to compare with the Photometer. Do you suggest leaving the CYA where it is and up my FC? Any thoughts on the cloudiness being caused by the high CYA? Pump has been going 24/7 for the 3 weeks I have been working on this.

John
 
Cloudiness is not being caused by high CYA, it's probably being caused by Algae - because your CYA is so high and your FC so low. You are literally stood on the cliff-edge at 5ppm.

Either raise your FC to a level appropriate for your current CYA (7+), or lower the CYA (via water changes) and then maintain an appropriate FC for that new level.
If it were me, I'd be grabbing a gallon of LC right now and adding it to the pool, bringing that up to around 10ppm

If you are SLAMMING, your FC for CYA of 100+ should be ~ 40ppm (and thats why we generally suggest a lower CYA number)

The only test generally recommended around here are the Taylor drop tests, as it's repeatably accurate and reliable.
 
I believe your CYA would be best at 60-70 for your climate. Running any pool at 100 CYA is VERY problematic. Next, consult the FC/CYA chart for the correct FC.

CYA does not cause or contribute to cloudiness, regardless of the ppm.

TFP is REALLY picky on the precision of test kits so we only use data from any of these four.....https://www.troublefreepool.com/blog/2019/01/18/test-kits-compared/

I suggest you perform an OCLT.........there is a good chance you have an algae bloom you can't see.

A pic of your pool water usually helps.
 
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SJPoe said:
Cloudiness is not being caused by high CYA, it's probably being caused by Algae - because your CYA is so high and your FC so low. You are literally stood on the cliff-edge at 5ppm.

Either raise your FC to a level appropriate for your current CYA (7+), or lower the CYA (via water changes) and then maintain an appropriate FC for that new level.
If it were me, I'd be grabbing a gallon of LC right now and adding it to the pool, bringing that up to around 10ppm

If you are SLAMMING, your FC for CYA of 100+ should be ~ 40ppm (and thats why we generally suggest a lower CYA number)

The only test generally recommended around here are the Taylor drop tests, as it's repeatably accurate and reliable.
Click to expand...
Thanks, I have 8 bags of HTH Super Shock so I can boost it quickly, going to drain some water and get a better CYA reading.
 
duraleigh said:
I believe your CYA would be best at 60-70 for your climate. Running any pool at 100 CYA is VERY problematic. Next, consult the FC/CYA chart for the correct FC.

CYA does not cause or contribute to cloudiness, regardless of the ppm.

TFP is REALLY picky on the precision of test kits so we only use data from any of these four.....https://www.troublefreepool.com/blog/2019/01/18/test-kits-compared/

I suggest you perform an OCLT.........there is a good chance you have an algae bloom you can't see.

A pic of your pool water usually helps.
Click to expand...
Thanks, going to do as you suggest and remove some water to get closer to the 70 CYA but I did document that I did a OCLT with a result of only 0.35 and have a CC reading of 0.25....attaching a before and after (present time)
 

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duraleigh said:
A SLAM with a CYA of 100 is really impractical......get your CYA reduced to around 60 or so to complete a reasonable SLAM
Click to expand...
To clarify my post, as Duraleigh says, Slamming (which it looks like you're attempting) with a CYA so high is very difficult.
Immediately, you need to get some FC in there to ensure the situation doesn't get any worse, and then you need to look at exchanging some water to push the CYA down to a more manageable level (60-70).
Liquid Chlorine is best - granular shock often has either Calcium, CYA or Copper in it - you really don't need any of those.

So, to directly address your original post :

taylormade said:
Hi, I have been struggling to clear up the cloudiness in my pool (I think it's because of the high CYA) for 3 weeks now. I opened to a green, swampy mess and am getting very close as my OCLT result is only 0.35.
Click to expand...
Assuming you have been following the SLAM process, and accidentally added stabilizer toward the end - you added too much, and now you need more FC until you can get your CYA back down. Aim for 8-10ppm, you won't have any issues with harshness or irritation as long as its in balance with the CYA

taylormade said:
Problem is, I added too much CYA and my reading is 95/105. I see it is suggested to have the CYA at a level of 70 for my SWG and keep the FC between 5 and 10. I also see with the Pool Math App that with my current CYA reading of 95/105 that a FC reading of 7 is suggested.....which is still within the 5/10 that is suggested if my CYA was 70.
Click to expand...
The recommended range is 7-10, not 5-10.
5 is the 'OMG Danger Will Robinson' level. The absolute minimum.

taylormade said:
I was just going to go drain a bunch from my pool to get the CYA in check but wonder if it's a waste of time/water/money....also wonder if keeping the FC at 7 (which seems high and maybe uncomfortable for swimming) is a good idea or a normal thing.
Click to expand...

Long term, having your CYA lower is better. You should aim for 60-70. With a Vinyl pool, you cannot drain a whole bunch and replace all at once or you risk damage to the liner - you'd want to only drain to just below the returns and then refill (like you were winterizing) - you may need to do this a couple of times to get your CYA down.

taylormade said:
This will bug me until I get opinions from people with more experience than me, hence my post. So should I remove water and get the CYA at a level of 70 so I can keep my FC requirements down to 5-ish, or should I leave things alone with my high CYA level of 95/105 and run with a FC closer to 7? Thanks
Click to expand...

So yes, the best option is to remove the CYA, for long term happiness. In the short term, get some extra FC in there (preferably via Liquid Chlorine) to avoid any 'slip-back' on your SLAM progress.
 
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Is it possible that the cloudiness could still clear up and I have no algae issue? I did my slam that's when I took the readings for OCLT and CC. I would say I (though I) completed my slam process 7 to 10 days ago but the water has been clearing ever so slightly day by day. I should note that I cleaned my filters just yesterday and that was the third time since I started this process 3 weeks ago.
 

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taylormade said:
I have 8 bags of HTH Super Shock so I can boost it quickly,
Click to expand...
That is Cal-hypo and while it saves you on the CYA front, that much calcium at once may cause its own cloudiness.

During the SLAM Process there always comes a time when you've killed the algae but it hasn't filtered all out yet. The battle basically shifts from a chemical one, to a mechanical one. You keep the FC up throughout, because brushing may expose new layers of algae, needing killing, and you don't want to risk losing any ground. As you saw with the passed OCLT, FC mostly holds at this stage and maintaining SLAM FC becomes much easier.

But you don't OCLT until the water is clear, with no visible algae, dead or alive. You can't really see your bottom to know if it's poofing when you brush, nor is the water clear.

Stay the course. You got this.
 
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Newdude said:
That is Cal-hypo and while it saves you on the CYA front, that much calcium at once may cause its own cloudiness.

During the SLAM Process there always comes a time when you've killed the algae but it hasn't filtered all out yet. The battle basically shifts from a chemical one, to a mechanical one. You keep the FC up throughout, because brushing may expose new layers of algae, needing killing, and you don't want to risk losing any ground. As you saw with the passed OCLT, FC mostly holds at this stage and maintaining SLAM FC becomes much easier.

But you don't OCLT until the water is clear, with no visible algae, dead or alive. You can't really see your bottom to know if it's poofing when you brush, nor is the water clear.

Stay the course. You got this.
Click to expand...
Ah, interesting, the Cal-hypo and the calcium hardness increaser I added might be the reason....plus maybe I need more time to filter out the dead algae. I did not mention that I screwed up because this is the first time (that I can remember) that I opened up to a green swamp and I actually threw 3 bags of the super shock in before I added the stabilizer and when the FC went for a dive the next day I did it again with two more bags and then again after I added the stabilizer..... Then I came here and found the proper way to do it :) (learn from my mistakes people) I am draining water now to get my stabilizer level good, then I'll keep filtering (while maintaining the recommended FC level) to see if it clears up, if not I'll SLAM again....sound good? Oh, one last thing for now :) is my CA reading of 85 need adjusting? Pool math says 50-550 but I have read that 200 at least is where it might need to be. Thanks for everyone's time
 
taylormade said:
learn from my mistakes people
Click to expand...
That's all any of us can do. And maybe accept that we need help sooner, to skip a few of those mistakes. (y)


taylormade said:
is my CA reading of 85 need adjusting? Pool math says 50-550 but I have read that 200 at least is where it might need to be.
Click to expand...
Vinyl pools don't need calcium, but gas heater manufacturers recommend having 200 CH.

The 550 comes from places with very hard water. They fight contant CH rise from all the evaporation when the fill water adds more. Without adding a large softener system, they're draining every year. If they saw 200 as the ceiling, they'd panic. :ROFLMAO:
 
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Newdude said:
That's all any of us can do. And maybe accept that we need help sooner, to skip a few of those mistakes. (y)



Vinyl pools don't need calcium, but gas heater manufacturers recommend having 200 CH.

The 550 comes from places with very hard water. They fight contant CH rise from all the evaporation when the fill water adds more. Without adding a large softener system, they're draining every year. If they saw 200 as the ceiling, they'd panic. :ROFLMAO:
Click to expand...
Good to know, thanks again!! I'll get her up there too.
 
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Not mentioned earlier it's important to know how high the CYA really is. The most you can measure is 100 so then you'd need to do a diluted CYA test before you drain to really know what it is so it's done once and not fill again to find it's still way too high.
 
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SJPoe said:
Are you testing for those numbers yourself ? The CYA test is logarithmic, you cannot 'interpolate' between the marks and come up with 95 or 105.

If your CYA is 100, your absolute minimum FC number should be 5. Better if it was 7.
My pool CYA is 80 right now, and the FC yesterday when Grandson and I was swimming was 11...no issues at all.
Chlorine is not what irritates your eyes etc, it's the Chloramines, and PH.
Keeping your FC so close to the minimum is just inviting algae - and you already know how much hassle that will be.
I'd aim closer to the higher end of the target scale, not the minimum. Having your FC at 11/12/13 will not cause you any issues.
Click to expand...
5% of CYA is a solid FC baseline, I second this advice.
 
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Thanks to all who helped me out here, happy to say that I am now algae free and crystal clear. I had to drain some water twice to get my CYA down to 70 and I then did another SLAM. I had never SLAMed as hard as I did this time (not knowing the proper procedure) and now that I did I have gotten rid of what I thought was dirt that always accumulated at the liner seams at the bottom of the pool daily (nothing bad but I am picky), no more dirt because it must have been dead algae and this went on for the last several years. Nice not to have to go and vacuum those seams every day.

Now I have one last worry, if I am to keep my FC level around 7, is this not bad for my solar cover? All I can find online is that anything over 3ppm FC is bad for the cover.....thanks
 
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