- I have a Pentair Clean and Clear Plus cartridge filter. The owners manual states the I should "introduce 3/4 pounds of DE per 100 spuare feet of filter area." However, in searching the forum, I haven't seen anyone else recommeding this. The manual states to do this "for first time operation on new pools". It is not clear to me if I must add more DE everytime I clean the filter or just when I replace the filters.

- A pool book that I bought recommends soaking the filter in dilute solution of trisodium phospate and muriatic acid. I am reluctant to do that as the owners manual says to just use plain water to wash off the cartridge. Besides which, it is not clear to me that any additional soaking is necessary.

- Finally, please indulge me in what might seem a stupid question. People say that their pool is crystal clear. My pool is too... until you turn on the light at night. Then the water seems full of particulate matter. Is this normal?

Thanks,

Steve