After a big costly mistake culminating on Sunday (I killed my entire newly sodded back yard - another story for another time), I told my wife, it was just probably going to be one of those days.
I have a SWG but we had alot of rain on Sat and swam alot with usually 8-9 people in the pool.
So on Sunday afternoon, when I tested, the TC was low and I was going to supplement the SWG with bleach. PoolMath called for 32 oz to bring it to 5 FC.
I added 32 oz of Muratic Acid instead of bleach. I was talking to my dad at the time and the bottle location had been switched for some reason since I don't keep them in the same spot. By the time the fumes were registering as MA, it was done. I am color blind so things like this I don't pay much attention to color.
Then I added Baking Soda instead of Borax to bring the PH back up.
In the end, by the end of the day, all was back in order and fine.
If I did not have TFPC knowledge, this would have been panic mode. Instead, I just tested, adjusted, repeat until everything is back in order and I had everything on hand that was needed. We were swimming again that night.