Hello Waterbear,

Here are the US Government’s numbers for the mean UV index for July (see here

http://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/gif_files/julavg.gif

Honolulu is 12, Phoenix 10 and Miami 9; my CyA at 35 sure works well with FC at 6. As stated we have minimal loss of chlorine.

Agreed that you have more extensive experience than I; and I really appreciate you taking the time out of your busy schedule to answer my posts. But the question still remains why a CyA of 35 in Hawaii with our elevated UV performs just as well as 60-100 CyA in states with lower UV?

Could it be that as Chem Geek pointed out there is minimal difference in chlorine loss after one reaches 35, do you think he is right, or possibly wrong?

Please note our mean UV index in August is 12 versus the other locations which are 9. In September our UV remains at 11, when the other locations drop to 7 or 8.

I agree that I am religiously following the water chemistry dictated by the "PoolEquations" spreadsheet but it is working for me.

pH 7.5
Alk 80
CyA 35
Calcium 425
Boron 50
Salt 3500

Please let me know what you think as I am no scientist. Maybe I am misinterpreting the datum.

Thanks again for your help.