Question about differences on site and PoolMath app


Active member
May 31, 2017
Melbourne, FL
I've been using the Trouble Free Pool app to manage my chemical balance for my pool. However, the app is giving different recommendations for FC than the pool school article "Water Balance for SWG". That article lists FC should be 4-6 ppm with CYA of 70-80, etc. I have everything but the CYA at the recommended levels and I'm currently adding some right now.

But at my current CYA of 60, pool math app says my target FC is 7 with a range of 3 - 9, and if I enter 70 for the CYA value that raises to 8 with range of 3 - 10 and at 80 it's 9 with a range of 4 - 11.

Which one should I use as 4-6 is a lot different than 4-11 with 9 recommended as target?


Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
Look at the [FC/CYA][/FC/CYA].

There is not really a "target" for SWG pools. It is just critical to keep the FC above the minimum.
The PoolMath webpage just reports the MINIMUM FC for SWGs and also shows a minimum and target range for non-SWG pools
I think the app has kind of combined this information.

This is an area that is being worked to be more clear and consistent.

Bottom line. For SWG pools, just try to keep the FC 1-2ppm above the minimum at all times.