Sand filter blowing dirt back in pool. Desperate for help!

[Leah]

Someone please help! I have a 24' round, 52' tall above ground pool with a Hayward sand filter,with multi setting valve. Don't know the model # right off. When I try to vacumn it blows the cruddy water right back into the pool. This year our pool started out dark green and gross. After much shocking we finally got the water mostly clear with lots of debris on the bottom. It seems to be working fine under normal filtration, but when I vacumm it immediately blows the crud back in and in minutes the water is murky and gross again. It's not just a little that goes back in, it looks like total sludge. The sand must be picking up some of the debris, as the pressure does rise, but I think it's mostly going back in.

It has been suggested that the filter can't handle the heavy dirt load, but we've vacummed heavy debris in the past with no problem. The sand was replaced this year. My husband said the spider laterals and pipe are all ok, he checked them when we replaced the sand. The gasket under the valve was in perfect condition too. The people at the pool place said maybe we need additional sand, and as an experiment told us to add a bag of the zeo sand to our regular filter sand and after each backwash add a cup of de to the skimmer to see if it makes any difference. It did nothing. The way things are, vacumming is useless and vacumming to waste isn't an option either. Takes too much water out of the pool for the amount I need to vacumm(which even with a properly functioning filter will take hours.)

I'm desperate for help with this, I'd like to actually get some use out of the pool before summer ends, but as it is, I'm so frustrated I'm about ready to tear it down. We barely used the pool last year either because of this problem, but we got frustrated with it and just let it sit. I really hope someone can give me some answers.

[floridapooltech]

Either one of two things are going on here.

1. When he replaced the sand, he did not put enough in, causing the debris and dirt to pass right through the sand sitting in the filter right now.

or

2. When he checked the laterals, he didn't check underneath them, or notice a small hairline crack in them. More common than not, this is going to be your issue as a cracked or broken lateral will ultimately lead to debris returning to the pool.