I have been keeping my pool at 20 FC the last 12 days and am still dealing with cloudy water. here are my test results:

FC 20 CC 1
pH - 7.2
TA - 70
CH - 500
CYA - 70
OCLT - 3 PPM
Sand filter

Looks like progress is being made! Since you're still losing a bunch of FC overnight,you need to keep at it! Are you sure there's not a bunch of goo at the bottom?

Make sure there isn't anything sitting on the bottom of the pool. You might also try bumping up the FC to about 28ppm for a 40% of your CYA value. I get this value from the chlorine/cya chart in pool school. Make sure FC stays at that level as much as possible. Also, keep the filter running 24/7 if it isn't already doing that. The real experts should be around soon.

I see one did post before I did. [End edit]

The pool is gunk free and I am still scrubbing daily. Yesterday we purchased a new suction pool cleaner as our old one was way worn out. We got a Baracuda MX8 is South Africa for about $220 (Finally found something cheaper than in the USA. Bumping the Chlorine up to 28 PPM.

Just be patient. Brush a lot, run the filter 24/7, and do your best to keep that FC up. You'll get there.

Look in the sand filter and check the sand quality. You better wear a body condom when you do this (or wear gloves). Replace the sand and then floc or just replace the water. Any other suggestions?

Using floc or replacing the sand is not something often recommended here on the forum. That said, removing the top of the filter and inspecting/cleaning the sand is probably a good idea once each year or so. If it has not been done for a while, i would do it.

Flocculant seems to have very mixed results. Most users report little or no improvement. A few however, report it absolutely did the trick. I would consider floc only after I had exhausted all other possibilities.

Have you seen gradual improvement over the past few days or does the clarity of the water seem stationary?

I wouldn't even consider any other treatment (like floc) until you stop losing FC overnight. That is a clear sign that you need to keep shocking! Checking the sand won't hurt, but I expect that it will be fine.

I have checked the sand twice since starting to shock. I buy my bleach in South Africa and have to travel a long ways to get it. I have used 33 gallons of 15% bleach and I have 6 gallons left. I am a little worried now that I am going to run out of bleach. We will see how the next few days go. I am still noticing a little improvement (at least I think I am). Hoping to wake up tomorrow with some more improvement.

I would get some more bleach so I would not be concerned about running out. Shock value for a CYA of 70 is up around 28 so only running 20ppm has probably slowed your progress somewhat. Sounds like you have everything on the right trick but are not quite holding your FC high enough.

Started shocking on October 14th and today we passed the overnight test and the pool is crystal clear. We ended up using 200 liters of 15% bleach. Now just a few pump problems to figure out and we are ready for the summer. Thanks for the help.

Yikes! That's 53 gallons of 15% chlorinating liquid for a 16,000 gallon pool. At $3.80 per gallon in U.S. dollars that's a little over $200. You had written that replacing the water would have cost $360 so I suppose this worked out better, but it still was more than usual. I wonder what was continuing to consume chlorine for so long and why the filter wasn't clearing the pool faster. We sometimes suggest adding some DE to a sand filter for finer filtration and faster clearing and in rare cases a clarifier or flocculant.

Not sure what was taking so long. I had all of the solids out of the pol within the first day or two. Wont be long till we are swimming now.

Congratulations. Hope you have a great swim season.

My problem is almost exactly like this -- I will create my own post, though. Mine also is taking forever to clear. I don't have pictures, but mine looks like this too.

I'm sorry, but 12 days.... 30 days.... that seems a bit excessive.

If we are measuring constantly, maintaining proper shock levels, keeping our chemistry in balance..... doing everything right...

Should it take this long?