According to our in-house chemists, they are now saying T/A really should be in the 80 to 100 range, though I have never had problems with a vinyl pool with it as high as 180ppm.

Try reading some of the stickied threads that Watermom, aylad, Poconos and I authored, especially on pool maintenance and BBB. They should make it a lot clearer.

Remember: in a vinyl pool you are concerned with pH and sufficient chlorine to keep it sanitary. Everything else serves those two thing--T/A helps keep pH constant. CYA(Stabilizer) helps keep chlorine from breaking down too fast. Calcium is only for hard-sided pools.

And most of the other chemicals and tests (phosphates and "Total Dissolved Solids") are designed to keep the pool stores and pool chem companies solvent.