My 24 foot above ground pool took about two weeks to get sparkling clear after I opened it in May. However two weeks later it started to cloud up in spite of maintaining chlorine levels including shock once per week. I attempted a number of things and then it started turning green - not slimed up but definitely green and even more cloudy. It has been very hot and dry here for over a month so that may have led to the problem in the first place, but it seems that my efforts should have worked. Here is what I've tried:

1. Chemicals properly balanced? Check. At least as best as I can tell from reading my test strips.
2. Lots of shock - 4 gallons in the evening into about 13,000 gallons of pool water. That eliminated the green but not the cloudiness.
3. I put a blue clarifier called Sparkle Super Clarifier into the skimmer as perscribed. It claims to be a combination flocking agent and an improver of my sand filter's (200 lb) performance. The bottle says it cannot be over dosed, so I thought it would be a safe one to use. Didn't do anything. Added more the next day and ran the filter until nighttime at which time I shut it off to aid in settling of precipitates. I vacuumed the next day. Still cloudy!
4. I've read that if the PH is on the high side of OK, lots of shock can contribute to the cloudiness, so I lowered it a little - looked to be about 7.2 after doing that. No luck.
5. Even after subsequently keeping chlorine levels high, it started to turn green again so I added four more gallons of shock plus two pounds of the dry shock. The water is blue once again but STILL CLOUDY!
6. I'm currently putting in daily maintenance doses of algecide to hopefully prevent the green as well as maintaining chlorine levels on the high side.

I replaced the sand this season, vacuum regularly and keep trying the above. I've backflushed but not overdone it since literature seems to indicate that overdoing that can reduce the filter's effectiveness. The only thing in the PoolSolutions Gotchas list that might apply here is the clarifier being the culprit in which case the claims on the bottle that it cannot be overdosed are false. Any thoughts?