Update: We were able to fully drain the pool last night, and started the refill immediately. The pool water (1/6 full or something) was G.R.O.S.S. this morning. I dumped in less than a 1/4 gal of 12.5% chlorine and particles started settling out right away and the water is clearing as it continues to fill. I added an equally small amt of CYA to get that party started, and I was so pleased that there was ample chlorine present at sunset, after the pool being in full sun all day. So, the starts of our fresh fill has already vastly improved our ability to hold FC in full sun. 