CYA and FC levels

[TravisD]

I had to go to the pool store yesterday to get some replacement parts for my ABG pool. While I was there I was speaking with an employee about how nice my pool has been since I have made the switch from Baquacil to chlorine.
Anyway, to make a long story short, he basically told me that I am keeping my FC level too high and that I do not need to use a higher level of FC just because I have CYA in the pool. Basically, he was saying the level of CYA has nothing to do with the FC level I need.
My CYA level is 40ppm and I have been keeping my FC level between 5 and 3 per the CYA / chlorine chart in Pool School.
He is telling me that I should stay between 1.5 and 3 unless I am shocking. He also said that a 16 FC level for shocking is too high.
This guy "seemed" genuine and did not try to sell me anything. He was very supportive of the BBB system I am using.
Now that I have gotten conflicting information in regards to FC level and CYA, I just want my FC level to be right.
I don't want to be "pool stored" and do the wrong thing. Can someone please reassure me?

 

[anonapersona]

Does he own a pool?

Does he run it that way?

Does he also use algaecide or other chemicals on a regular basis?

 

[duraleigh]

Travis,

There are literally thousands of pools kept just like yours around the country. You should not lose faith in the suggested levels in chem geek's chart. They work.

Keeping your FC as low as the PS suggests is an algae invitation.

 

[Butterfly]

Travis, rest assured you are doing the correct thing by maintaining your FC 3 - 5-ish based on your CYA of 40.
In fact, sounds just like my pool :-D

Although the pool store person seems genuine, he clearly does not understand the relationship between CYA and chlorine.
This is all too common an experience for folks going to the pool store.

Stay confident with the BBB method. It works.
When your friends'/neighbors' pools start turning, um, green, they may come to you for help

 

[TravisD]

Thanks for the reassuring words everyone! I have gotten so much great information off this site that I was confident I was right, but he put that little bit of doubt in my head.
So he is wrong for saying that you do not have to increase FC levels in relation to CYA levels, right?

 

[JasonLion]

Correct, you do need to raise FC levels as the CYA level goes up (unless you want to have problems, which will force you to go to the store more often and spend extra money on things from the store to solve your problems).

 

[chem geek]

Travis,

If this guy at the pool store knows any chemistry at all (which he may not), have him look at this paper which definitively determined the chlorine/CYA relationship.

There are also more links to additional scientific studies showing the relationship of chlorine and CYA in this post.

You might ask him why he believes there isn't any relationship. Is this something he was told by a manufacturer's rep?

Richard

 

[tedinelkgrove]

You can not refute scientific research and data. One fact he did leave out, follow his advice and you'll have a backyard algae farm in no time. Maybe the real inspiration behind his genuine act...you come back to buy lots of chemicals to combat your green pool.

 

[TravisD]

Alright, thanks again for reassuring me that I'm doing the right thing. I am now 100% convinced that he has no idea what the relationship is between FC and CYA. I might even print that up and give him some reading material if I see him again.
Thanks again for setting me straight!