Hi Steve;

I'm gonna 'pull rank here and close this thread to EVERYONE except me, Chem_Geek, Waste or Waterbear.

It's taken me 15 minutes to chart out all that's gone on with your pool, and work out what might be going on. Mostly, I think you've done what was needed, but you're getting see-sawed around a bit. (History table below)

So, here's what I think, based on what I've read and pieced together.

#1 - Your initial CYA was > 150, since you've drained more than 2/3 and still have ~50 ppm. Draining was a good thing.

#2 - You are fairly clear -- but some of the lack of clarity may be well water. Do you know what's in your well water? Most wells have some minerals / metals.

#3 - You should ignore CC levels of 1 ppm or less when your chlorine is > 15ppm, and stable. You report no change (22 => 21 ) overnight . . . so your chlorine is stable.
(There is some bleed over into CC readings, as chlorine gets high -- don't know why, but I've seen it repeatedly. Pools in full sun with stable chlorine levels do NOT have significant CC levels . . . no matter what the test shows UNLESS you've added something really strange to the pool.)

#4 - Your pool is greenish, but high in chlorine and clearing up. I'd recommend going ahead and swimming. Just tell your wife to wear that old 2-piece or bikini she want to replace anyhow -- she'll be fine, but 20 ppm FC w/ 50 ppm CYA will be hard on Lycra swim suits.
(You may like the results, however -- I have some fond memories of swimsuits my wife had that had lost some of their 'substance'! Might not want the neighbors over though. ;-)

#5 - You should feel the sides of your pool. If there is no slick/slimy feel . . . the green color is NOT algae, rather your algae is gone, except maybe for cracks and crannies.

#6 - Green clear pools can be a result of some peculiar iron conditions, but will clear up in a few days (maybe a week) if you just keep your pH in range and keep chlorinating.

#7 - At this point, I think trying to 'fix' anything with your water, as opposed to simply being patient and staying on course would be a mistake.

#8 - Haven't looked at your filter thread, but if there's anything wrong with the filter's function, fix it! Pools do NOT stay clear from chlorine alone!

Enjoy your pool!

Ben



10K pool, 2nd year of use
+ opened green with leaves & sludge
+ 2 weeks of being pool-stored
+ used 3" tablets
+ sand filter, regularly backwashed

05-21
+ 20 gal bleach

05-22 - Sunday
+ 5 gal bleach + 1# CYA + 1# 'shock'

05-23 - Monday
+ 10 gal bleach
+ some improved clarity; brushed

05-24 - Tuesday
+ pH 7

05-26 - Thursday
+ added 1/2 box borax
+ chlorine high (test strips)
+ phosphates "extremely high" (per pool store)

05-27 - Friday
+ FC 40, CC 1.5
+ ph 7.2
+ CYA > 100ppm

05-28
+ drained 2/3 or more

05-29
+ FC 15; CC 0.5
+ pH 7
+ CYA 50

06-01
+ PM FC 22; AM 21