CYA A Double Edge Sword Rant and Rave!

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knackll

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Apr 2, 2011
30
I have come to the conclusion besides me, there are quite a few people that just do not understand how important of a component CYA is to the chemistry of a pool. It has literally frustrated me this season because of my own ignorance.

Anyone who does not understand the role this plays in your pool water should be very concerned. Case in point, I may have inadvertently damaged my brand new liner because I have been running a high FC level of 8 or higher all season long trying to keep the algae at bay in a well chlorinated pool. The only thing I managed to do is possibly bleach my liner below the water line.

Now, my wife swears she doesn't see the difference but I do. All because of the Stinking, Ignorant, sales people that want to push their Chlorination feeders and Tri-chlor pucks! Oh yah, lets not forget about the local guys at the pool stores also ignorant to CYA as well.

The CYA as important of a component of the chemistry as it is necessary to control the chlorine that is consumed in the water. It absolutely needs to be between what is recommend on several places on this site which is 30-50ppm. There is no other discussion about it. Any higher than that, causes you to add too much chlorine. Regardless if you have a liner pool, Gunite, blowup I don't care. It causes you to add too much chlorine which leads to other problems. I get how important it is to have it but if not controlled it can literally ruin your pool.

Last year was my first year with my new pool. The water couldn't of been any better. This year has been a year from heck! I've spent hundreds of dollars on chlorine and a Taylor 2006 test kit (should of had it anyways) and water due to draining several times, trying to keep algae out. And for what? Because I was ignorant to the CYA levels which just continued to climb due to Tri-chlor pucks.

I have since reversed my problem by draining my pool 2' and dropped my CYA from 100ppm to 70ppm (still too high) but it is a little more manageable.

I think what has frustrated me was coming across a debate on this forum of CYA and proper levels. I just keep seeing all these debates about it. There is no debating the fact that anything higher than a CYA at 50ppm is trouble and costly. I'm living proof.

I've learned my lesson the hard way. No more Tri-chlor which someone said to me never say never. The BBB is for me no doubt in my mind. I will do everything I can to maintain 30-50ppm and stay there.

Seriously people, these guys on the website get it! Listen.....

My 2 cents....well you can add a couple hundred to that.

Sorry for the rant!
 
To pool school! :)
pool-school/water_balance_saltwater_generator

Short story, SWGs are really just for maintaining FC. So the CYA helps to keep it steady and within range. With an SWG we have a lower chance of going too low, so shocking is not very likely to be required. Also, we only keep an average of 4ppm of FC in the pool... the water is sanitized as it passes through the high FC environment in the salt cell.
 
FC 8 at what CYA? If the CYA was really high - I don't see how the bleaching would have happened. The resident expert Chemgeek could point you to the right data but even much higher average FC levels can be OK at high CYA as far as bleaching etc. It's just COSTLY.

My pool runs a FC level of 5.5 - 9 most of the time. 5.5 is my ending FC most nights, 8.5-9 is my starting FC most nights. My CYA is around 50. My point is that all night long it's at around 9. No bleaching so far - but only have been at this for a month and a half. My liner is old and bleached but the bleaching is on the floor and from previous owners powdered chemical use. I assume stuff was tossed in when they couldn't see and they didn't stir / brush enough.
 
You are very right about the importance of cya, but I think you might be off base as that being the cause of your liner issues. If your cya was high then you effectively have less "active chlorine" in the water for a given amount of measured FC. People with liner bleaching often have either high concentrations of chlorine staying on the liner (due to poor circulation) or have very low cya combined with high FC. In addition, probably the most damaging thing to a liner comes from ph being outside of the recommended range (especially low ph).

Back to chlorine/cya relationship ...For example: If you have 30 ppm cya and you keep you pool the normal high FC level of 6 ppm (for that cya concentration per poolcalculator) then you active chlorine level is about 0.1 Cl2. If you have 70 ppm cya and hold your FC level at 6 ppm, then you active chlorine level is only ~0.03 Cl2...much less "active chlorine", i.e. less damaging then when you are at 30 ppm cya.

Bottom line, if you maintain a lower cya and a high FC, that has the most potential to bleach a liner, though if you follow our guidelines for proper chlorine/cya balance, then you will not have problems.

If you want to read more, this is a good discussion of it by chem geek: http://www.troublefreepool.com/pool-water-chemistry-t628.html...but watch out, it is a "deep end" subject.
 
I think most of the liner bleaching that tends to occur when there are high CYA levels is not from a maintained relatively high FC, but instead from the extremely high levels used during shocking as well as the likelyhood of frequent algae blooms and their related need for shock.

Ike
 
Isaac-1 said:
I think most of the liner bleaching that tends to occur when there are high CYA levels is not from a maintained relatively high FC, but instead from the extremely high levels used during shocking as well as the likelyhood of frequent algae blooms and their related need for shock.
Click to expand...
Good points, but the op did talk about trying to maintain a high cya pool. At 8 ppm FC at 100 ppm cya is only an active chlorine level of ~ 0.03 ppm Cl2...not enough to do much damage, assuming it is well mixed. Even if occasionally the chlorine got up to say double that or 16 ppm FC, it would only get to an active chlorine level of 0.05 ppm Cl2. Even if the op was shocking the pool, the active chlorine level for 39 ppm FC, would be about 0.2 ppm Cl2...or equal to about 0.5 ppm FC at 0 ppm cya.
 

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Isaac-1 said:
I think most of the liner bleaching that tends to occur when there are high CYA levels is not from a maintained relatively high FC, but instead from the extremely high levels used during shocking as well as the likelyhood of frequent algae blooms and their related need for shock.

Ike
Click to expand...
This person may be exactly right as to what has damaged the liner. It makes perfect sense. I'm howver not going to debate about the CYA levels of 100ppm not being an issue. I can understand what you guys are talking about the liner bleaching. Trying to prevent the blooms by shocking most certainly could of cause the bleaching. Eitherway the root cause is what? CYA being too high.
Its too high at 100ppm period. As for SWG I can not comment as I have no experience on that.
Thank you for everyone advice asit means alot.
 
linen said:
knackll, any chance you could post pictures of the liner damage?
Click to expand...
The water line is not visible at this point because I refilled the pool. It is really only noticeable when I drain it for winterizing or for the obvious reason of removing the CYA.

I do not mean to be so aggressive, but when the debate begins with CYA levels are not high at 100ppm, then why is there premature physical damage to a brand new liner at the water line. And I mean light color below the water line not above. Why is my chlorine not working anymore. Why I am I spending over $$$ this year in chlorine that I did not spend all of last year. It frustrates me, because some people just don't understand or refuse to based on their experience or what they think they know. There has been a change in my pool water and the only change that has been identified is the frequency of algae growth causing the high consumption of chlorine. I have said in prior posts that all the other chemicals are perfect except for high FC and CYA. Sure I can believe the chlorine staying in the 8/9's maybe higher may not have directly caused some bleaching, but most certainly from the frequent shocking to prevent the algae blooms could have.

Either way, it there is no defending a high CYA from the point it is non-economical & damaging (indirectly). Just a waste of money. I might as well of just thrown the cash in the garbage, less stressful.

My pool experience tells me so.

First year no problems, all is wonderful. This year nothing but trouble. If I never see a 3" tri-chlor tablet again it will be too soon!

Thank you,
 
You post too fast knackll :) , here is my response to your previous post:
knackll said:
Trying to prevent the blooms by shocking most certainly could of cause the bleaching. Eitherway the root cause is what? CYA being too high.
Its too high at 100ppm period.
Click to expand...
If chlorine is applied incorrectly, then it can damage a liner. If it is applied to a pool correctly, there is very little danger to vinyl liners assuming the amount being used is correct for the amount of cya in the pool.

Bottom line, unless you allowed your chlorine to rest directly on your liner (i.e. did not pour it in front of a return to disperse it, or if you allowed it in concentrated form to settle some where..such as dichlor/trichlor resting on the bottom), it should not damage you liner, even at shock levels.

I am not trying to be argumentative here, but I do not believe high cya was your root cause for your liner issues. Low ph however, is a more likely culprit. Were you using dichlor/trichlor previously?
 
knackll said:
linen said:
knackll, any chance you could post pictures of the liner damage?
Click to expand...
The water line is not visible at this point because I refilled the pool. It is really only noticeable when I drain it for winterizing or for the obvious reason of removing the CYA.

I do not mean to be so aggressive, but when the debate begins with CYA levels are not high at 100ppm, then why is there premature physical damage to a brand new liner at the water line. And I mean light color below the water line not above. Why is my chlorine not working anymore. Why I am I spending over $$$ this year in chlorine that I did not spend all of last year. It frustrates me, because some people just don't understand or refuse to based on their experience or what they think they know. There has been a change in my pool water and the only change that has been identified is the frequency of algae growth causing the high consumption of chlorine. I have said in prior posts that all the other chemicals are perfect except for high FC and CYA. Sure I can believe the chlorine staying in the 8/9's maybe higher may not have directly caused some bleaching, but most certainly from the frequent shocking to prevent the algae blooms could have.

Either way, it there is no defending a high CYA from the point it is non-economical & damaging (indirectly). Just a waste of money. I might as well of just thrown the cash in the garbage, less stressful.

My pool experience tells me so.

First year no problems, all is wonderful. This year nothing but trouble. If I never see a 3" tri-chlor tablet again it will be too soon!

Thank you,
Click to expand...
I think we both agree on high cya being a problem. :cheers: It could be that your trichlor usage caused repeated low ph that over time that did the damage to your liner. Was the fading all around? If yes, then it is likely low periodic low ph and not bleach that caused the problem. FC at 8/9 ppm with a 100 ppm cya level will not cause fading all around a pool.
 
PH is fine and always has been (7.4). I was using tri-chlor since the beginning last year. I have dicontinued the use of it indefinitely. It's not the PH.

I think were getting away from the original concern, which is basically the education of CYA. Understanding it's part in maintaining a good pool chemistry with out any economical consequences and/or stressful situations due to poor pool chemistry as a result of mismanaged CYA.

My pool liner really is not the debate. It is what it is.

Thank you
 
High CYA sucks. The fact that the only solid pucks that work in autochlorinators are made using CYA sucks. The fact that the industry doesn't understand or plays ostrich with CYA sucks. The fact that pool store tests are inaccurate particularly with CYA sucks.
 
linen said:
You post to fast knackll :) , here is my response to your previous post:
knackll said:
Trying to prevent the blooms by shocking most certainly could of cause the bleaching. Eitherway the root cause is what? CYA being too high.
Its too high at 100ppm period.
Click to expand...
If chlorine is applied incorrectly, then it can damage a liner. If it is applied to a pool correctly, there is very little danger to vinyl liners assuming the amount being used is correct for the amount of cya in the pool.

Bottom line, unless you allowed your chlorine to rest directly on your liner (i.e. did not pour it in front of a return to disperse it, or if you allowed it in concentrated form to settle some where..such as dichlor/trichlor resting on the bottom), it should not damage you liner, even at shock levels.

I am not trying to be argumentative here, but I do not believe high cya was your root cause for your liner issues. Low ph however, is a more likely culprit. Were you using dichlor/trichlor previously?
Click to expand...

Look, obviously nobody on this site has see my pool, and I understand that. All the suggestions are really well received and thought out in my mind as possibilities. So it really is appreciated. I have a 1-1/2 hp pump circulating my water extremely well. I do not treat the water when the pump is off. That said, shocking methods definitely could help exacerbate the liner problem. But, that would never of happened if the CYA was at a normal level. I wouldn't have the need to shock because the chlorine would be doing it's job. However with a CYA of 100ppm the chlorine was beginning to become less effective.
Bottom line keep your CYA between 30-50ppm. This should help prevent over chlorinating the pool.

Thanks again for your advice as it is well received.
 
I hesitate to even get into this, but think that for any newer members reading this, it needs to be made clear:

The point is at higher CYA levels you need higher FC levels to maintain the same active chlorine level ... stay at the correct FC level, you have no algae and no fading.

At higher CYA levels, the shock FC level is higher, stay at the recommend shock level for your CYA and you will kill the algae and not fade the liner.

Get frustrated by algae because your FC was too low for your rising CYA, drop a nuclear amount of chlorine in the pool, kill the algae AND fade the liner ... this is not recommended.

If the FC is kept in the correct range (normal and shock level) for whatever the CYA is ... you will not fade the liner.
Keep the pH in the correct range (7s) ... you will not fade the liner.


I completely agree that when the CYA gets too high, problems (algae) is likely to result. And it is horrible that most pool stores do not understand the CYA/FC relationship. But, equipment damage is not directly due to the high CYA.
 
jblizzle said:
I hesitate to even get into this, but think that for any newer members reading this, it needs to be made clear:

The point is at higher CYA levels you need higher FC levels to maintain the same active chlorine level ... stay at the correct FC level, you have no algae and no fading.

At higher CYA levels, the shock FC level is higher, stay at the recommend shock level for your CYA and you will kill the algae and not fade the liner.

Get frustrated by algae because your FC was too low for your rising CYA, drop a nuclear amount of chlorine in the pool, kill the algae AND fade the liner ... this is not recommended.

If the FC is kept in the correct range (normal and shock level) for whatever the CYA is ... you will not fade the liner.
Keep the pH in the correct range (7s) ... you will not fade the liner.


I completely agree that when the CYA gets too high, problems (algae) is likely to result. And it is horrible that most pool stores do not understand the CYA/FC relationship. But, equipment damage is not directly due to the high CYA.
Click to expand...

Well said Thank You & an eduction helps too!
 
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