Randy,
I agree with redtop03. I have 4 drains into my sump/refugium. One feeds the skimmer by gravity from the tank and 2 of the other 3 have socks on them. And I have socks on both drains in my frag & grow out system. I got a bunch of socks and change them every 3-5 days (that,s 4 socks each change). I save up the dirty socks in a big rubbermaid tube with a lid ('cause they smell). As I get down to my last few clean ones, I deal with the dirty ones.
First I fill the rubbermaid tub with water to get the socks all wet (I use a hose out in the yard). After 30 minutes or so, I put them in the washing machine and do a big load wash with Oxy Clean (which is hydrogen peroxide, not soap). I don't do a rinse yet. I do a 2nd wash with a cup of bleach, then I let it do a rinse. The bleach does the socks good and cleans up the washing machine too. Then I air dry them and put them in a flip top plastic box for storage until I need them. I do a load every 6 to 8 weeks... I have a lot of filter socks!