I keep a record too. I used to keep it on a mini-excel spreadsheet in my PDA. Now I just write it on the cover of my old PS233 in pencil and erase it at the start of the new season. I'm SO lazy I use each column twice, dividing each row into an upper and lower entry.

I never use the pool calc. I know I have 19,000 gallons, so I figure 20,000. I know if I add half a gallon of 12.5% LC it will boost my FC by about 3ppm, and a full gallon by 6ppm.
My CYA was at zero, so I chlorinated with Tri-Chlor tabs until the week that CYA finally read over 30ppm.
I checked my pH and when it was low (like 6.8, 6.9), I dumped in a box of Borax. An hour later it was still low (and my T/A was VERY low) so I dumped in a box of A&H Washing soda. My pH up to about 7.6, where it has remained constant for almost 3 weeks, despite my TA never going higher than 60ppm.

But if the Pool Calc helps you, by all means, use it.

The B-B-B method is all about sensible and logical pool maintenance so that your pool can be what it's SUPPOSED to be: A Wreck Creation facility (if you have kids you understand this!)

Carl