Nylon filter socks

[ReefMadness]

nylon socks are definitely easier to keep clean but for longevity I recommend hand washing and never using the machine to clean them. they aren't terribly durable and even a gentle cycle caused threads to run creating gaping holes.

[Razor Ramon]

I buy mine off eBay 150-200 micron felt for $2.00 I have like month worth.
So one day a month I wash in the washer with bleach inside out twice and rice again turned the right way then let dry for a day, done for another month.
The nylon ones are on eBay I have some of them I use them only if I need to run some media through the tank in a hurry, felt are much better for clean reef waters.