Standard 20 micron filters can be bought at Amazon, Home Depot, and Lowes. They are around $20-$25 each. We reccomend changing / washing out your filters frequently based on your use. For individual use, we reccomend changing / washing filters once every couple weeks. For commercial use, we reccomend changing / washing your filter every several days. We reccomend draining the Mini-Me Cold Bath at least once per month for individual use. If many people are cold plunging, then we reccomend weekly / every several days.