Oh, this is great! OK, two things! First, thanks Mick for that insight, that may indeed be all that's needed! Its true what he says GoGator, if you have other larger biomedia areas in a filter, its ok to change your "fine mechanical" filtration (the "thin wool" as he calls it or "blue wool" as you call it) as frequently as needed, as it shouldn't even have a measurable effect on your biofiltration. (If you want to prove it to yourself the first few times just do a few before/after ammonia and nitrite tests to confirm whether the removal of the wool caused a "mini-cycle" as we call it, which would be trace measurements of ammonia or nitrite showing up after the change, when they weren's there before.
OK, the second thing is that I wasn't sure about your communication until your latest post but now I think what I'm hearing you say is that its the -commercial- filter pack with the carbon in it that you've found to be doing the slowing down whereas your own homemade one doesn't and your original question was just asking whether it seemed safe to just use 2 homemade ones and chuck the remaining commercial one altogether. (apologies if this seemed obvious to you all along, somehow I couldn't make it out!)
Well, in answer to that I say absolutely! Chuck the commercial one and go with your homemade ones that are working! You are just confirming that you are a member of the club here of hobbyists who are not afraid to experiment all the time with media!
~~waterdrop~~