redneck,
You should only need to shock when you get combined chlorine (chloramines) above 0.5 ppm. That will probably happen more easily in your locale than farther north, but if you're maintaining your water chemistry correctly, you shouldn't need to do it on any kind of a schedule just because you live in Florida.

The amount of chlorine you need to keep in your water is a function of the amount of stabiliser you have in it. Use Ben's Best Guess Table (http://www.poolforum.com/pf2/showthread.php?t=365) to find the minimum and shock levels you need for your CYA level (you'll need to determine that a little closer than 50-100ppm). Again, you should only need to shock when your combined chlorine gets to 0.5 ppm. To know that, you'll have to test your water regularly with a good test kit.

Lowering your pH will have only a temporary effect on your alkalinity. If you want to lower it permanently you'll have to follow Ben's procedures to the letter.