You just need to act on the basis of what your tests showed; I can't advise more than that.

I don't see what kind of filter you have, in your signature. If you can carefully vacuum to waste, that would be probably be best. What you want is to vacuum with as little water as you can, moving as fast as you can without stirring up the floc. You may want to try vacuuming, while someone else adjusts pump speed for you.

Of course, if you have no "waste" position, you'll have to vacuum to filter. In that case, you want again to go as quickly as possible, with as little water as possible, with one more point: keep the pump speed down so you do NOT over load the filter, or push the floc through.

I'd love to hear how it goes!