Recommended FC level with SWCG

[paulio]

Hi All

My TF100 test results are currently this:

FC 3
CC 0
TA 70
PH 7.6
CH 300
CYA 70
SALT 3800


So I think pretty balanced for SWCG. If i up the FC level on the chlorine generator one point (i.e from 6 to 7) FC shoots up to 5.5. IS it better to run FC at 5.5 or OK to run at 3. I know the recommended level in pool calc is 3 but elsewhere on the site it says FC of 3 is the borderline minimum and recommended is between 3-5 for my CYA level.


Thanks for you advice,

Paul

 

[BoDarville]

Welcome to TFP!

An FC level anywhere in the 3-5 ppm range is good for your SWCG pool. An FC of 5 is considered the target and 3 is the minimum that it should not drop below. The target level give you a little bit of extra cushion against the FC dropping to below 3 ppm. If you were having a big pool party, I might give a one-time supplemental dose of chlorine (using liquid bleach - not by dialing up your SWCG) to bump the FC level 1-2 ppm above the target of 5 to account for the increased chlorine demand from an unusually large number of bathers. But for normal everyday use, 3-5 ppm is fine.

Here is the Chlorine / CYA Chart.

 

[paulio]

Hi BoDarville

Thanks for that! Now I'm curious as to why the pool calculator says 3 is the suggested level instead of the minimum level. Do you know why it says taht?

 

[linen]

Hi BoDarville

Thanks for that! Now I'm curious as to why the pool calculator says 3 is the suggested level instead of the minimum level. Do you know why it says taht?

I agree that the description in the PoolMath calculator could be better worded. The swg field is a minimum, the range listed for normal pools is exactly that the min and max, and the shock level and Mustard shock levels (also known as SLAM levels) are targets. You can cross reference this in this pool school article: http://www.troublefreepool.com/pool-school/chlorine_cya_chart_shock