Well, it's done. The pool is fine. I don't know what happened. I mean, I know what we did, but don't know why it didn't work before.

With my neighbor, who also has a pool, as witness, I opened the filter, and removed the grids. We looked over everything. He saw and verified that the manifold was properly seated. Then I cleaned the grids and had him inspect them, and he verified that they were fine. I reseated the manifold, reassembled the filter, and off we went.

The only difference was that he was meticulous about bleeding all of the air out of the system, which I wasn't, but have never been, yet the filter didn't stop filtering until 2 months ago. And even so, there's a big bubbling every time the filter starts up, as air gets into the water for a little bit.

He also insisted that I put the full amount of DE in, seven pounds worth. I usually go a bit less, and it's never been an issue. Whatever did it, it worked. I'll be damned if I know what happened. Guess he has good pool mojo, though he's often struggling with it, too.

His theory is the manifold rising up and sucking back down, but I don't think so.

I also think I see a tiny bit of DE in the pool at night, but can't be sure.