Buddog,
ANY flushing is better than none, so yes, you can flush after the trichs start to change from clear to cloudy to amber...in fact, this is when you SHOULD be flushing!
By "flushing" you mean feeding nothing but plain ph'd water, correct? (just so we're on the same page).
Are you feeding organic nutes? Adding any carbo (sugar) loads to it?
ISO