Great explanation & info! Many thanks!

Update: luckily I waited till I heard back. Glad I did. We had a few days of serious ran (4+") here in the Balt. Wash. area. My Ph dropped to 7.0 - 7.2 from 7.8 but I did add two 4lb boxes of baking soda. Numbers seem pretty good now. Ph is 7.4 & TA is 90. FC has slooowly dropped to about 7.5 ppm. No CC. I guess the water was pretty free if organics. Cya is up to about 30. Calcium hardness up to 320.

I guess it's best to leave well enough alone for now. Water is crystal clear. Thanks again for all your expert help.

Charles