Filtering pre-boil wort?

i'm doing a partial BIAB batch at the moment. i finished my mash and noticed that there was a lot of solid material in my wort - "grain dust" floating in the liquid. either my grain was crushed too fine or the bag's holes/netting is too big. i decided to filter out a lot of the solids by running all my wort through a fairly fine strainer. i did this to limit how much trub makes it into my fermenter, and to filter out any husk material that might be in that dust (believing that it would result in tannin extraction during boil - probably not a lot, but some).

bad idea? anything i should be concerned about?

yes, i know, i should RDWHAHB... well, i'm HAHB at least

Not a bad idea. In fact, that is (or should be) part of all all-grain brewing processes. It's called the vorlauf and it's intent is to remove grain/husk material from the wort before sparging into the boil kettle, usually by recirculating the wort through the mash for a few minutes. This prevents tannins, amongst other benefits.

TB