Sad to say it's back. I had the panty hose on the return took it off tonight to test to see if it was the sand being too high. The pump turned on and within 5 minutes it was all over the bottom of the pool.

Could it be possible that the pump is so oversized that when it starts up it forces the fine stuff right through the laterals? I vacuumed about an hour ago and so far there is nothing else on the bottom. Hopefully the fact that the dust comes out right when the pump starts up will lead to some answers.

I turned the shut off valve about 1/2 way off and it raised the pressure from 15psi to 20psi on the filter so we'll see what happens when the filter comes on in the morning. The return jet was so strong before you couldn't even put you hand over the return itself.