FC vs CYA Question

Jump to latest Follow Reply
C

chesterton

0
Apr 26, 2016
6
Tyler, TX
OK guys I have read through a lot of information here and have a question in regards to FC:

I understand the TFPC chart of FC vs CYA and it makes a lot of sense, however, why is this not more readily available from other sources? I get confused as to why most test strip kits (I know they aren't accurate) and pool stores would tell you to maintain FC levels of 1-3ppm without regards to CYA levels? This would seem to be a bit short-sighted and cause major problems with pool water especially as CYA levels increase. I am 100% agreeing with the TFPC method and plan to follow this websites recommendation, so I am not doubting anything on TFP at all, this is more out of curiosity for my own mind LOL...
 
One reason is that pool stores are in business to sell products with more markup than bleach and baking soda, etc. They are also primarily promoting the use of pucks to chlorinate, which constantly raises CYA (i.e. constantly changes the required FC). This concept would be impossible to effectively communicate to customers - many people don't want or care to know. Further, they may not really accept or buy into the theory behind the FC/CYA relationship. But mostly it's too hard for pool stores to quickly communicate those ideas to the masses and it's not a great business profit case. The philosophy here at TFP is understanding what you put into your pool and why. The philosophy of pool stores (and not a bad business concept really) is to have the customer put their faith in the pool store and be reliant on them to sell you what is needed. And then when you have "chlorine-lock", just drain 3/4 of the water and re-buy their chemicals to re-balance the water.

I think it's great that you are curious, and that you found a great place to help you maintain your pool inexpensively and safely. Others may be able to lay out the Pool Store conundrum better than I.

Feel free to continue to utilize the resources here and especially Pool School. Pool School. There is a graduation ceremony after you open your pool to clear water next spring!
 
Thanks guys for the responses!

It is funny after reading your responses and thinking back to last time I went into the pool store after they tested my water. I starting asking the guy helping me about the pucks and CYA levels and how to prevent CYA levels from rising. He kinda nodded his head and said that basically you just have to drain some water to get CYA level back down. He quickly moved the conversation along to all the different chemicals I need based off the testing they performed and I politely told him I would take those into consideration and left. I am not saying he was deliberately trying to deceive etc, but it does seem like a very good business model to have customers completely rely on your testing and recommendations to keep their pool looking great.

Anyway, I have a lot more to learn here and have already learned enough to feel fairly confident about maintaining my pool. I will hopefully get my TF-100 test kit in today or tomorrow and may post up some numbers just to get feedback from all the experts here!

Thanks!
 
Easy answer for me! What he ^^^^^^^^^^^ said!

I LOVE that you are asking questions! You will learn SO much and THEN be able to help others!

How I learned what I did was reading a section at a time. You will see someone with a problem and all of the ideas and answers to get it fixed.

Kim :cat:
 
I wonder if anyone has had any warranty issues keeping FC at higher levels?

The pool guy my pool builder sent told me I was at risk at damaging my equipment when he tested my FC at 4 - referencing the "industry standard" 1-3. We all know this isn't true, but is totally what they teach in CPO.
 
from what I've seen here, the whole cya/FC relationship goes back to one research paper from the 70's, in conjunction with a bunch of user observations. Major industry is probably not going to make a major change without more research and lab results, and if nobody is doing that research, the "old standard" ways just continue.
 
BuckeyeChris said:
from what I've seen here, the whole cya/FC relationship goes back to one research paper from the 70's, in conjunction with a bunch of user observations. Major industry is probably not going to make a major change without more research and lab results, and if nobody is doing that research, the "old standard" ways just continue.
Click to expand...
The strange part is that it isn't a major change. Its a 4ppm difference in recommended FC level at most.
 
pinguy said:
I wonder if anyone has had any warranty issues keeping FC at higher levels?
Click to expand...

It is up to a pool owner to know the requirements for their warranty. There are some stories in the archives of owners being bound to certain ranges to keep their warranty valid, some even being required to submit occasional water samples to verify their compliance. Seeing how quickly some heaters have been destroyed by low pH I can understand the strictness of such requirements. In those cases the owner just has to work around it, by keeping their CYA low or other means of getting by with a low FC.

I think BuckeyeChris has it, the standards are the standards and have been for something like 50 years. Most of the people in the industry don't follow the relationship not because they are afraid of losing money but because they don't even consider that they might be incorrect about something they have known their whole careers.
 

Enjoying this content?

Support TFP with a donation.

Give Support
JoyfulNoise said:
Chem geek's Post #32 is particularly informative - blind faith and this forum? - Page 2
Click to expand...
The EPA limits FC to 4ppm :suspect:

I suppose that sheds a bit of light on the 1-3 standard

But it also begs the question...how are all these commercially run pools following 1-3 not having more issues with water quality? Low CYA and more frequent (several times per day) testing than a homeowner would do?
 
FC is defined as the sum of active chlorine (HOCl/OCl-) and chlorinated cyanurate (chlorine bound to CYA). That is what the test measures and that is what the industry defines FC as.
 
you'd need to take your FC and do the math with your CYA. chem geeks old posts may have a table in them somewhere, but there's not a test for "Unbound" chlorine.

Outdoor commercial pools have a much higher demand and have more robust chlorination methods, in addition to other sanitizing methods that are overkill for a residential pool. They are required to test throughout the day. If you are testing a lot, and only using OTO tests, then I suppose it also makes sense to have your FC target in the 1-4 range so you can use that test.
 
BuckeyeChris said:
you'd need to take your FC and do the math with your CYA. chem geeks old posts may have a table in them somewhere, but there's not a test for "Unbound" chlorine.

Outdoor commercial pools have a much higher demand and have more robust chlorination methods, in addition to other sanitizing methods that are overkill for a residential pool. They are required to test throughout the day. If you are testing a lot, and only using OTO tests, then I suppose it also makes sense to have your FC target in the 1-4 range so you can use that test.
Click to expand...
But that calculation is based off the science the pool industry is not accepting, which lands us back at square one.

JoyfulNoise said:
FC is defined as the sum of active chlorine (HOCl/OCl-) and chlorinated cyanurate (chlorine bound to CYA). That is what the test measures and that is what the industry defines FC as.
Click to expand...
Literally by that definition, it's impossible to recommended a FC level without knowing CYA. Madness.
 
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