Looks like you are scrubbing the air before it goes into the cooltube and ducting. This is sort of bad, cause any small little leaks or gaps in either the cooltube, or the ducting will allow un-scrubbed air to be exhausted out.
You'll want to figure out a way to make sure that every single little gap is sealed. THat insulated tubing is hard to work with and keep sealed properly, as opposed to that vinyl dryer vent hosing you have, which is easy to seal with some silicone glue, weatherstripping, neoprene gaskets, hose clamps, and my favorite - Aluminum tape.
You're gonna want to really seal the hell out of all that ducting and vent box, and make sure theres no gaps between the insulation and the outer wrapper in that tubing, other wise unscrubbed air will pass through.