I was very suprised when the pool water turned green then brown after using the metal filter, but once I saw I could trap the "color" in the socks I went that route, just replacing the sock filter until rinsing produced little - no color. I took a picture of the rinse water to show how nasty it was, but couldn't upload it.

I wonder if I stuffed the sock filter with those "color catcher" sheets they sell in the laundry isle of the supermarket, if it would help catch color faster, maybe it wouldn't take 5 days at the beginning...hmmm. May sound silly but unless and until we're committed to buying a better/bigger pool, we can't justify spending hundreds on a sand filter. Also, it didn't help that we had to patch about 15 holes just in the air ring and another 6 holes along the sides this year...at this rate next year we'll have more patches than pool!

When I bought the metal filter, I saw an "organic filter", I'm guessing that's the one I should have purchased for tannins.