I was wondering if anyone could point me to an article or give advice on the frequency of backwashing. When I backwash my filter the psi reads 17. I have rarely, if ever, seen my psi reach 27 which seems to be the suggested psi for backwashing. Although around 23 or so I do have very dirty water coming from my discharge pipe when I do backwash. Currently I have not backwashed in 3 weeks or more and my psi is just below 20; this even after adding D.E. to the filter to help with filtration. I have heard and read that you need to backwash once a week or when you pressure reaches 10psi over normal. I'm not sure my psi will ever reach 27! Right now my pool is clearer than it has ever been thanks to this forum. How should I approach backwashing is my question. Thanks.