oneyellowbird - Why are TFP's recommended levels different

[oneyellowbird]

Chem Geek - Your above Pentair IntelliChlor link shows CYA 50 - 80 PPM (page 10). I have the same Installation Guide and my booklet shows CYA 30 - 50 PPM (page 10). I have an IntelliChlor IC-40 Ver 3.02 installed 5/2013 manufactured 7/2012. Has Pentair changed their CYA recommendations? I've been holding my CYA at 40. From this thread, should I increase it to 50+ ?

 

[chem geek]

You are right that I see their latest manual says 30-50 ppm. I'm not sure why they made the change, but maybe it's because at their 1-3 ppm FC that algae would develop at their higher CYA level. Instead of properly changing their FC range to go to 4 ppm, they instead lowered the CYA range. That will require a higher % ontime and that will have the cell wear out faster so it's in their economic interest to go that way.

If you have an SWCG with a pool exposed to full sunlight, you should set your CYA higher, as much as 80 ppm, and set your FC target accordingly so 4 ppm FC if you have 80 ppm CYA. That will have your SWCG last as long as possible.