Thanks, ladies. Good thoughts all. I do have rain barrels, and two 600gal. rainwater cisterns. That water is 'reserved' for the orchids, vegetables and fruit trees. Even with well over 1000 gallons in reserve I run out of rainwater on a regular basis in the hot, dry months in spring and fall. The fatal flaw of collecting rainwater, it doesn't replenish itself when you need it the most, right? Spring and fall are the main growing season for vegetables here, and also the driest times of the year.
But the rest of the landscape - about 1/4 acre - is watered during the dry months with the well water that comes from 150ft. underground, and runs through Florida's fabulous limestone aquifer. I was thinking of something as simple as a drip system into the pump, with vinegar or something else acidic. But it would probably use gallons and gallons of the acidifier and be high-maintenance and expensive. Maybe if I post my question in the Farming forum somebody will have an idea, do you think?
Treating the acid-lovers with some aluminum sulphate might be my solution if I can't find a way to balance the well water reasonably. Thanks!