So I've had the pump running all weekend.....I spent about an hour on Saturday scrubbing the pool. I vacuumed the whole thing on Saturday morning as well. Tried to be extremely thorough. I had my 13 year old go around on Sunday and scrub it again. I pulled the stairs out and let them dry out. Then Sunday I scrubbed them down in all the nooks and crannies with bleach. I also realized that I was storing my vacuum head and hose in a dirty plastic bin. So I scrubbed that out and let the vacuum head soak in the bleachy water for a few hours to make sure it was completely disinfected. Kept the FC level up around 15 all weekend. I have no CC according to my tests, so that's good.
Bottom line is that the water appears pretty much crystal clear again. I dropped the ladder back in last night and the kids were swimming again. I had to work today, but I'll do a full battery of tests one more time when i get home today to make sure everything is ok. I plan on pulling that ladder out once every couple of weeks, too, and giving it a good scrub. Maybe I'll just pull it out at night and let it dry out more regularly.
So I think I've got it figured out. Thanks for all the troubleshooting advice, guys and gals! I am going to show my gratitude by officially becoming a TFP Supporter!
I can't quite figure out the CYA test exactly....I don't know when I should consider the black dot on the bottom of the cylinder to no longer be visible. If I really look closely, I can barely see a faint outline of it when it reads "30" on the cylinder. But I also know I put in quite a bit of CYA at the start of the season to get it up from about 20.....I was thinking I was at about 45, but apparently I was not. Maybe that's why my chlorine got eaten up and it must have dipped too low just long enough for the algae to take hold. I think I need a little more CYA, would like it to be up around 40 so I'm not going through a ton a chlorine. I think we've had sooooo much rain lately that I probably have lost a lot more water through the skimmer than I realized....and twice I've had to siphon some water out of the pool because the rain had completely filled the pool to where it was over the top of the skimmer.