Good morning everyone,

My baseline filter pressure is 12 psi. I uncovered the pool June 1 and here it is June 22 and the psi has not changed. The pool stays very clean; the few leaves I've gotten I've fished out with my leaf net. Most debris involves bugs and silt coming down from the trees, and of course it gets filtered with my 1 hp Superpump (sand filter, 20,000 gal in ground). I get a small blob of debris in the bottom of the deep end occasionally and it just takes a minute to hook up my vac hose and take care of it. Of course I brush the pool every week.

If we get no crazy tropical storms this season and my psi stays this low all summer, then theoretically I should not need to backwash at all (I know that dirtier sand cleans better and over-backwashing is hard on the system)? And, if this remains the case, should I backwash anyway when I cover pool in September? Although there will be 8-9 months downtime, I will run pump anywhere from 10-15 times in the overnight hours when temps drop below 28 overnight during the winter months so the pump will not be totally inactive during that time (I live in the south).

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With a CYA of 50, when I opened to a crystal clear pool after 9 months down time, I shocked to 15 ppm. Since then I continue to find no combined chlorine. Since I lose about 2.5 ppm a day under full sun I bring the ppm up to 4.5-5.0 each night (with household bleach). So the 24-hour range is 5.0 ppm to 2.5 ppm. I am the only swimmer in the pool most of the time, swimming several times a day, but I think this qualifies for a low bathing load.

Conventional pool advice, we know, tells us to shock every 10 days or so (no matter what), but if I have no CC, and crystal clear water, I shouldn't worry about shocking until I have CC (or signs of algae)? My water is completely odorless and in fact even after swimming there is no trace of chlorine smell on my skin.

One more question: if I get .5 ppm CC should I shock, or wait until I get 1.0 ppm? I apologize that I haven't the time here at work to search the archives. Thank you!