So, opened my 19300 gal round Monday. My FC was 3 and I wanted to shock it (it was clear, but I like shock on opening). Just FYI my CYA was 75 so I was shooting for an FC of 31 just to be safe. So, I goto the pool calculator and put in my numbers. I used 8.25% bleach from wally world (@ 2.98 for 121 oz, FYI). I calculated 815oz of bleach to shock. So, I put in seven 121 oz jugs in (only needed 6.73, but what's 0.27 of a jug between friends).
Checked my FC today....the good news is that there might not be any yellow algae in there...the bad news...the FC was 39.
Luckily, the water is still cool and in a week I will need to add more bleach here in sunny Arkansas.
I really don't want to do a partial drain to reduce the CYA. Bah..