Cloudy water in pool

[preeti22]

I've got a 20x40 foot pool, in ground, salt system.First four years, never-ever had any problem in keeping the water in check.But now the water became cloudy. Local pool store said water checks out perfect chemically. They (guessed) and told us to "add this" and "add that". Nothing worked. I changed filter sand, that seems to work for about three days. But after that water is still cloudy?

What's going on?

 

[addy1]

no clue, if it was a cloudy pond I could offer some suggestions. My pool in arizona was a sand filter. Maybe you need to back wash the sand more often. Are you in a hot or cooler area?

 

[sissy]

Could there be to much salt and your getting a reaction from the liner and the salt .I know cement based ponds can do that .Could something around there contaminate the water like pine tree needles or sap from them .The this and that could be making it worse .They do the same with ponds add this add that and they want to just keep selling you stuff so they can make money .Sure there are no clogs in any plumbing that is keeping the filter from doing it's job .