I have maintained my pool for the last 16 years including opening and closing. This is first year using the TFPC method. So far been its working perfect. I wish I had come across this forum years ago. Anyway I bought the TF-100 kit and it is my best buddy. Couple months ago when I was a "newbie" at the TFPC method ,my PH was a bit high so I thought I would pickup some borax and lower it!!! I know your smiling , needless to say I picked up some muriatic acid soon after. Guess that's the last time I make that mistake. PH is now back around 7.5 after that blunder. So Thanks to all the info on this forum. Look forward to learing more in future.