I got some good info here including a link to a great site with step by step instructions for many DE filters. Ends up I had extremely dirty/clogged grids and cracks in my manifold. I replaced all of those last weekend and all seems to be running like a top now. And the water has cleared very quickly. I'm kicking myself (and cursing the pool company I paid to help open this year - it's my first time and I didn't know about this site) for not looking into the filter as a contributor to the slowness of getting water clear.