I could be your poster child for what 10 seasons of pucks and Cal Hypo shock look like. But I've found your site, done lots of reading, am ready to covert to BBB, and it looks like my first step is to lower my 100+ CYA (Taylor test, dot disappeared far below 90 line). I've also read about the dangers of draining a fiberglass pool and the precautions that must be taken. If I wanted to try a 50% drain, does anyone know if that is as dangerous as a full drain?