A very fine material that’s placed over the skimmer basket to filter out small items. One prime example when a skimmer sock is commonly used is during the Spring when the flowers are putting off their pollen. Skimmer socks help trap the pollen before it’s able to find it’s way into the filter.
For anyone new to using skimmer socks, one thing you want to avoid is placing them in your skimmer and then turning the pump on for several hours or so without checking on them. You will need to clean these socks frequently, especially during the pollen high season. By frequently, I mean after running the pump for as little as two hours if you have a high infestation of small pollen debris. The socks will catch the debris as they are designed to do. But if it gets too caked up, it will starve your pump of water. Best way to mitigate this is to get several pair of skimmer socks and rotate out the dirty ones with clean ones. Then immediately clean out the dirty ones so they will be ready for another round of duty.