Monthly pool chores include shocking the pool as well as scrubbing down the side walls. Checking the filter and running standard routine chemical checks are also recommended.
When it comes to monthly checks and maintenance for an above ground-pool, the truth of the matter is that most things either need to be done throughout the month several times, or they need to be done daily. For shocking the water, this should be done at least once every other week. This is a process of using a highly concentrated chlorinated powder to shock the water in the pool. This helps really kill off any resilient bacteria that the standard daily processes aren't accomplishing.
Brushing of the side walls should be incorporated as a routine chore throughout the week. If it is maintained, then it will not grow out of proportion to the point of growing dirt and algae. As far as water treatment and chemicals are concerned, routine daily checking of water levels alleviate any chances in chemicals dropping or rising to some sort of disastrous high or low. Some individuals find that hiring outside pool companies to come in once a month a great help, but there is essentially no need unless under physical restrictions.