Thanks for the Chlorine explanation. I am just confused as to how it went from OK to none in one day (92 degree day)

CYA - I'm not sure my test kit does this. I looked up the one that is being recommended and will add it to the list of things to purchase.

I will do an ALK test and post the results later this evening.

I was always told not to test pool in the middle of the day.... any truth to this?