My wife used to say we needed a son named "Frank" so I would not be (frank).

But I'm gonna be, anyhow: the odds are VERY high that you are simply overlooking the problem inside the filter.

If you can't find it yourself, get another filter. In theory, you could hire someone, but most of the pool guys I've seen couldn't find their way around a DE filter with 2 flashlights, a manual, and a factory rep helping!