How often do you run a undergroud pool filter?

It depends on the size and type of pool filter, as well as the amount of usage the pool gets. Generally speaking, it is recommended to run a pool filter for 8-12 hours per day. This can be done continuously or in cycles. For example, a pool filter can be run for 4 hours in the morning, 4 hours in the afternoon, and 4 hours in the evening. It is important to run the pool filter long enough to ensure that all of the water in the pool passes through the filter at least once per day.