Bump help needed!

[vallan]

I have a Hayward DE filter. I was cleaning up a lot of winter algae on the bottom of the pool and the pressure went up, so I bumped the filter, feeling a lot of resistance on the handle. I kept an eye on the pressure as I cleaned, and when it went up again (the algae was bad) I went to bumpt it again - and there was no resistance on the handle at all. Bumping had no effect. I had to flush out the filter and re-coat. It worked fine, but then when I went to bump it, still no pressure and no effect. Anyone know how I can fix it? Thanks.