Cloudy water


LifeTime Supporter
May 26, 2010
Central Connecticut
Helping a friend. They have an 18x36 in ground pool 5' deep. Still have slight cloudiness. We're told by pool store to change sand in filter. I am trying to convert them to bbb. I used my tf100 to test their water. Here are the results.

FC 12.5
Cc .5
Ph 7.5
TA 150
CH 140
CYA 45

Sand filter pressure at 12 psi

Pool slightly cloudy. They were told to "filter aid" ? Help. I can't see anything obvious.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
How long has it been since it was worse? Sand filters can take quite a while to clean up the water, often a week or more. If everything is working there should be a visible improvement from day to day, but it can still take a while.

There is no point in changing the sand. Adding a little DE to the sand filter might help, using clarifier might help. Neither is by any means certain to help.


TFP Expert
LifeTime Supporter
May 10, 2010
SW Louisiana
With .5CC and cloudy water shocking may be the safe thing to do, just keep in mind even after everything is dead in the water it still takes a while for a sand filter to clear it out. To answer your question about replacing sand, around here it is generally felt that sand rarely needs replacing, you may need to open it up and clean up the gunk from the top layer of sand, but in reality the sand is usually good for the life of the filter housing. A lot of people here swear by adding a small amount of DE filter compound to their sand filters (this will get flushed out during back washing) to aid in clearing up a cloudy pool, there are also liquid floculants you can add to help speed the process. If this is worth the extra money, vs giving it more time is up to you.