Slow the drain and be patient. Palmer's book recommends 1 liter per minute. I've timed my runoff, it's like a piss trickle at that rate.
What's your water to grain ratio? I've found that high water ratios sometimes take longer to run clear as it takes longer for the grain be to compact. But that's just my experience.
Also, don't expect crystal clear runoff. Just recirculate until the little bits and pieces don't drain out.
BTW, you using wheat or oats? Also how was your crack, was it really fine with a lot of powder?