Getting ready to close my pool. Just tested by pool installer. TC is 10.0 (I think their test system will not register above 10.0 but I think TC is above 10), FC is 10.0 (but again I think limited by test system), pH is a 7.7, TA is 165, CH is 300, CYA is 135. Reading the TFP Pool School items leads me to believe the TC should be less than .5 while the FC should be about 3.0 and CYA should be about 50. Should I plan on replacing about one half my water come Spring while opening and if I do, will the TC to FC ratio come in line?