Eliminate “Minimum” column on CYA/FC chart?

Saturn94

Well-known member
Mar 11, 2015
1,002
SE Virginia
I see so many posts all the time where pool owners are using the “Minimum“ FC number as their target, then don’t understand why they have issues when their FC is “fine”. It makes me wonder if having the “Minimum“ column is more confusing than useful.

Has there been any discussion about eliminating the “Minimum“ column to make it very clear where FC levels should be kept?
 
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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,216
Tucson, AZ
The FC Min represents the minimum amount of chlorine needed to maintain an appropriate disinfection rate (kill time). Going below that value doesn’t necessarily mean that pool water is unsanitary, it simply means pathogens have a greater probability of being transmitted person-to-person. Even at the minimum FC values, there still enough chlorine to keep algae at bay (algae is not pathogenic).

What the minimum FC does not represent is the reserve chlorine needed to overcome loss to UV and swimmers (bather load). That is a highly variable figure that can only be determined through testing and use. The Target FC value typically adds enough extra chlorine to compensate for daily losses in an average pool.

Teachable moment .... not everything can be summarized in a table or a chart. So if someone chooses to use the TFP method of pool care and stays at the minimum and gets in trouble with algae .... then it’s a teachable moment if they choose to use it and ask a question. There’s is a amazing amount of detail and richness in the information on this forum...people just have to be conscientious enough to spend some time learning.
 
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Saturn94

Well-known member
Mar 11, 2015
1,002
SE Virginia
The FC Min represents the minimum amount of chlorine needed to maintain an appropriate disinfection rate (kill time). Going below that value doesn’t necessarily mean that pool water is unsanitary, it simply means pathogens have a greater probability of being transmitted person-to-person. Even at the minimum FC values, there still enough chlorine to keep algae at bay (algae is not pathogenic).

What the minimum FC does not represent is the reserve chlorine needed to overcome loss to UV and swimmers (bather load). That is a highly variable figure that can only be determined through testing and use. The Target FC value typically adds enough extra chlorine to compensate for daily losses in an average pool.

Teachable moment .... not everything can be summarized in a table or a chart. So if someone chooses to use the TFP method of pool care and stays at the minimum and gets in trouble with algae .... then it’s a teachable moment if they choose to use it and ask a question. There’s is a amazing amount of detail and richness in the information on this forum...people just have to be conscientious enough to spend some time learning.
Your great explanation should be included on the chart. ??
 

Buzsaw

New member
Apr 27, 2020
4
Texas
I'm new here, but am wondering why TFP's mininum and target chlorine ppm's are so much higher than the liquid chlorine bottle's recommended 1-3 ppm for unstabilized pools and 1-1.5 for stabilized?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,543
Laughlin, NV
I'm new here, but am wondering why TFP's mininum and target chlorine ppm's are so much higher than the liquid chlorine bottle's recommended 1-3 ppm for unstabilized pools and 1-1.5 for stabilized?

TFPC uses science to determine the appropriate FC/CYA ratios.