Thanks! I've brushed it and let it settle since my first post. The water quality has cleared by about 50% compared to late last night. There is no longer any greenish tint in the deep end even after brushing. I can't quite see the drain yet, but I can clearly see down the walls and into the corners of the deep end! I'll pull another test this evening and try the 0007 tip to see if I can get a better reading on the Ph/TA levels. I was afraid the chlorine was influencing these and it probably is. In the meantime since we're safely at shock level and have a cloudy day today I'll just stick with brushing - it doesn't look like I have anything to vacuum at all.

I'll take your advice to wait on the Ph/TA issue until the chlorine falls. Right now since it seems to be clearing so quickly I may not have a clarity issue. I think it's too early to tell. In the meantime I'll backwash. I haven't been doing that daily because I've been confused on the filter efficiency issue - since sand filters work better when they're slightly dirty I don't want to backwash but I've been wanting to get any filtered algae out of that sand. Our pressure hasn't gone up (normal is 18) so I've held off. The last backwash was right before we did the partial drain on Sunday. I'll now backwash daily until we're clear and try the DE. I still have one bottle of blue clarifier left but I don't think it will help (hasn't to this point!) and I don't want to put anything other than bleach, borax, baking soda and MA in the pool now that we've gone through 'detox'!

You guys are great! This is the first time we've had a problem but I'm not sorry because I found this forum and feel for the first time like we're totally in control of the pool. Thank you so much!!