I'm trying to solve a problem involving our Hayward 60sf DE filter: it recently stopped filtering.
The pressure gauge reads low, like it does after backwashing but before charging with fresh filter media. The pump isn't making unusual sounds (nor the filter), and the flow "looks" good despite lack of filtration. By "looks", I mean the surface disturbance and the circulation of floating objects all look like the pool does right after backwashing. I would normally perceive a gradual slowdown and increase in pressure as the filter approaches needing its next backwash. Over many days and an increasingly murky pool, the pressure has gone up a little, but nowhere close to where I normally do a backwash, and nowhere near as fast as normal under these water conditions. I see no bubbles anywhere (e.g., if there were air leaks).
I already replaced the grids (which were due) and later the manifold (which has failed before, causing mostly similar symptoms). Neither made any difference.
What else goes wrong with these things that would produce this kind of trouble?