I was told in June by the pool guy, that I should drain pool because that is what I need to do to keep the pool stabilized. Bought house spring of last year and he has been tending to it since. Since I bought the house a little over a year ago, they check and brush/skim the pool and add chemicals as needed. In the spring this year they also took all four cartridges out of filter and hosed them off and re-installed. Charged me 150 to clean filter cartidges, and stated that would cost me somewhere around $200 for them to drain/fill and add chemicals once full again. Pool is getting expensive to maintain with those two things and $110 a month for them to clean once a week. Any advice about draining and refilling myself?