Didn't you post this same question six weeks ago? Several responses
were given. See: http://tinyurl.com/cvtqo

"Dave Schwartz" wrote in message ...
I have a 25,000 in ground with a Hayward EC65 diatomaceous earth filter. I
have been in my house for 13 years. The filter has been here all along and
has always been very good. This year, I am getting a lot of earth going
into my pool. There are large clumps of earth in the deep end mainly, not
much, if any in the shallow. I had someone come over to look at it, and he
thought that the earth was entering the pool through the returns and it was
due to the age of the filter and that I should get a new filter. Maybe this
is true, but I am 98% sure the earth is getting in through the skimmer. The
largest clumps on the floor are near the skimmer. I have only one skimmer
and 2 returns. The return in the deep end is opposite the skimmer. It is
not impossible that the earth is coming out of the return and shooting
across the pool and landing under the skimmer, but I really don't think so.
The shallow end, which has the other return, has very little, if any earth
on it. I figure, if the earth is entering the pool through the returns, it
should be under that one too, which it is not. Also, I have seen the earth
rise up out of the skimmer and enter the pool. So, let's assume I'm right.
Why would that happen after so many years? Is it normal for the water to
reverse a little at night and bring the earth with it? My filter is
supposed to have a check valve. Wouldn't that prevent this from happening
if it was working properly? Could it be that?
Thank you for your time, and if anyone can give me suggestions, it would be
appreciated.

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Dave Schwartz
Commack, NY