Is my sand filter working?

[raven2963]

Its taking forever for the cloudy water to clear up. I can pour a pool chemical in the skimmer such as bleach or algecide. and I can see it entering the pool thru the return.. Normal?

[BigDave]

Liquid chemicals, yes; dry chemicals, no. To test a sand filter, slowly pour a cup of DE (from pool store) into the skimmer with the filter running and watch the return. If the DE comes out the return, you have a problem with the sand filter.

[PoolDoc]

. . . membership updated.

DE test info here: http://pool9.net/de-test/

[raven2963]

I have some food grade DE.. Can I use that?

[Watermom]

No.

[PoolDoc]

The problem with food grade DE is that it's an unknown quantity for us, with respect to filtration. If your DE is LESS coarse then filter DE, it may go through even a properly functioning filter. If it's MORE coarse than filter DE, it may be caught by even a non-working filter. It *might* be the same as filter DE -- food grade baking soda is chemically identical to pool "alkalinity increaser" -- but we don't know that.