I very much appreciate the help all. Everyone, including my dad, agrees that my CYA level is high, and it would be better to lower it. He seems to think he wouldn't worry too much with a 140ppm level, but it may just be because water costs them so much more in the San Antonio area.
I don't want to use any more chlorine than necessary, so I think I'm going to start draining it tonight and let my submersible pump run over night, and aim for draining half of it, even if it takes me a week. Then refill from the garden hose.
So, considering water temps is about 63 degrees, and it may take me a bit to get back up to skimmer level to get the pump running, am I risking a big outbreak? Should I throw anything in the water in the meantime to prevent that?