Took all the grids out today, cleaned them off, wife and I inspected each for the tiniest of tears/holes, could see nothing.
TIL that the bottom of the grid stand illustrates just where to put each grid! Like I say, "too soon old, too late smart!"
Replaced the spider gasket in the multi-port. Took over an hour to get the old one out and the channels cleaned! Used an exacto knife, a round "scraper" and finished off with Goo-Gone and sandpaper.
Reinstalled grid filters, added a little clean slurry to test, started pumping/filtering, and still have what looks like the fresh new DE coming out! Should I leave it pumping for a while? Is there a way to test the manifold? Should I just spring for a new manifold (about $70)? Reading some reviews on amazon about the manifold and it seems like they have a short life span. True?
The multi-port valve seems to work ok.
Follow up....ordered a new manifold today....local dealer wants $135...same part # on Amazon...$70 w/free shipping!
thanks again to all who have stayed with me in this quest.